Guide:Making money

Money is an essential part of Terraria, as it allows the player to buy items from NPCs. There are 4 types of coins; Platinum, Gold, Silver, and Copper. Platinum being the most valuable and copper being the least valuable.

There are several ways to earn money:
 * Killing monsters and bosses.
 * Selling items to NPCs.
 * Finding coins in pots and chests.
 * Using Silt Blocks, Slush Blocks, and Desert Fossils at an Extractinator.
 * Opening crates.
 * Taxing your village.
 * Picking up coins from the Leprechaun o'Fyffe.

Crafting and Farming
The following tables show different ways of making money. In this case, they compare the resources needed to earn in profit. For example, crafting and selling Ale is very simple since it only requires one item, Sand Blocks. However, it does require a lot of repetitive digging (1000 blocks). Instead, some people might prefer selling Fish Bowls, since harvesting Goldfish is more interesting. You can also buy lesser mana potions, craft lesser health potions, making Restoration potions and selling them.


 * See also: Guide:Gardening


 * Far left column - item sold to the NPC
 * Middle column - raw ingredients required for crafting
 * Far right column - Notes

Note: the Sand Blocks are not used directly; you need to craft them into Bottled Water or Mugs first.

Note: Armor Statue sell for 60 copper.

Note: If you have full hearts and sufficient Heart Lanterns, selling Life Crystals can be profitable, as they sell for  each.

Note: Endless Quivers sell for each, and are very simple to make, only requiring 160 wood and 160 stone each (assuming you craft the arrows.)

Torches
Farming Torches requires Wood and Gel.

Torches are just about the easiest and simplest thing to farm, as wood is plentiful and can be easily regrown. Torches sell for each and are produced in stacks of 3. The limiting factor is going to be Gel, i.e. you'll run out of it before running out of wood. Slime statues connected to timers, paired with lava or dart traps connected to timers can make an automatic gel farm.

Gel sells for each (Note that the spawned slimes will not drop money) and wood is worth  each (if crafted into Chairs). Crafting torches therefore "costs" and will yield  ( for each torch), for a profit of.

Each stack of 99 Gel together with 99 Wood will create 297 Torches. The crafting will net you  more than selling the chairs and raw gel.

Torches can sell for quite a bit more when upgraded to tiki torches, but this diminishes your wood resources a lot faster. Each wood spent on a tiki torch would be worth, the torches themselves worth. The total profit from each tiki torch is.

Another fast way to make money using only Wood is to buy some Torches from the Merchant for, then craft them into Tiki Torch and sell them back for , making a profit of for only three wood.

Lesser Healing Potions
To produce these you'll need: Once you've gotten a little further into the game this becomes a good option. If you haven't yet started a farm for Glowing Mushrooms then making Lesser potions is still quite good, and will suffice until you can start growing shrooms. As with torches, the fruits of your labor will be useful to you throughout the game: having a lot of healing potions on hand is always good.
 * An Alchemy Station
 * Sand, for making bottles
 * Mushrooms
 * Gel, by the truckload

Expected Profit: and  per 30

You'll need twice as much gel as mushrooms, but mushrooms are harder to come by unless you specifically farm for them. See the gardening guide for more on that. Two gel are only worth, a mushroom is , and 2 bottles are for a total cost of  for 2 potions. They sell for each, giving a net profit of  for 2 potions, or   for a stack of 30.

Tree farms work well for farming gel, as the flat open spaces seem to spawn tons of green and blue slimes.

Healing Potions
A Healing Potion requires:
 * 2 Lesser Healing Potions
 * 1 Glowing Mushroom

Advantages:
 * Healing potions are extremely profitable, selling for each.
 * Glowing mushrooms are easy to farm in large quantities, requiring very little maintenance compared to regular mushroom farms (which must be regularly "weeded")
 * Healing potions are more effective at healing than their lesser equivalents, and most players will be making them for this purpose anyway.

Expected Profit: and  per 30

As mentioned earlier, 2 Lessers cost in raw materials, and Glowing mushrooms are  each. Subtract this from the sale price and our anticipated profit becomes   per potion, or   for a stack of 30. Actual profit is slightly higher, as Lesser Healing Potions can be found in pots and chests all over the place, as well as bosses and dungeon shelves.

Tip: Never buy your Lesser potions from the Merchant. Lesser Healing Potions cost when purchased from the merchant. If you purchase Lesser potions and sell Healing potions, you will spend and gain, a net loss of  per potion you craft.

Shine and Night Owl Potions
Shine Potions and Night Owl Potions use the following: Both kinds of potions sell for just like Healing Potions. They are an excellent source of income to supplement a Potion economy, as they use largely the same ingredients as healing potions and the additional ingredients are easy to farm.
 * An Alchemy Station
 * Sand, to eventually transform into Bottled Water
 * Daybloom Seeds and a place to grow them, either grass or clay pots
 * Glowing Mushrooms or Blinkroot Seeds

Expected Profit:  per 30

The cost in ingredients is higher, but this balances with the fact that all the ingredients are so easy to farm. Both herbs are each, glowing mushrooms are, and the bottle of water is. This gets you  per Shine potion in profit, or   for 30. Night Owl Potions net  per potion, by contrast, so if you're overflowing with both Glowing Mushrooms and the fast-growing Blinkroot, make the Shine potions and either sell the leftover Blinkroot or combine it with Cactus to make Swiftness Potion.

Obsidian Skulls
Obsidian is worthless on its own, but you can make Obsidian Skulls from it. They require 20 Obsidian per Skull. You'll need:
 * A large amount of Lava
 * A large amount of Water
 * A Nightmare Pickaxe or better

Obsidian is easy to farm infinitely with liquid duplication. It's also easily created in the lower parts of the Cavern level.

Expected Profit:  per 250 Obsidian minimum, more if you get lucky modifiers.

Skulls sell for each, resulting in   per chunk of Obsidian, putting it in the top tier of ores. Every so often, you may craft a skull with a modifier on it; they sell for more than ordinary skulls. Obsidian Skulls don't stack, so to avoid a lot of trips back and forth just make a spare furnace and set it down within range of a selling NPC. Once you're in the buy/sell menu you can scroll down your crafting list to make skulls and immediately drop them into the NPC's inventory to sell them.

Ectoplasm
Expected Profit:   per stack of 99 ectoplasm

Enemies in the Hardmode Dungeon (after killing Plantera), when killed, have a chance to turn into Dungeon Spirits. They drop 1 or 2 Ectoplasm each, which sells for each. You can also craft them into Ghost Wings, which will give you more profit; the Wings can be sold for each, while the materials are worth  and ). The only hard part is farming the Ectoplasm, as Hardmode Dungeon enemies are stronger than the average enemy. You can also wire a chest statue or a shark statue to a mob grinder in the dungeon, both sharks and mimics can become dungeon spirits.

Stained Glass
Expected Profit: per single gem (any type except diamond) + 10 sand block

Take 10 blocks of sand and using a Glass Kiln make 5 glass, then use a workbench to make 20 Glass Wall. Now combine them with any gem except a diamond to get 20 Stained Glass, which sell for (for a stack of 20).

This is the most profitable use of non-diamond gems, with the possible exception of using rubies to create a Slime Crown to summon and defeat the King Slime.

Glass Kilns
Expected Profit: and  Per 99 Glass Kilns

Iron/Lead is a very common ore and torches are very easy to make also, the only limit is that iron/lead is limited to the world. Slime statues and a giant cave will make money making fast.

In Hardmode, however, farming The Destroyer is much more profitable, and 7 Mechanical Worms can be created with the Iron/Lead needed for two Glass Kilns.

Eye of Cthulhu and Eater of Worlds/Brain of Cthulhu
Demonite Ore (Corrupt World) or Crimtane Ore (Crimson World) occurs sometimes in the wild, but the best source is from defeating Eater of Worlds (Corrupt World) (or) Brain of Cthulhu (Crimson World) or the Eye of Cthulhu. You'll need all the best equipment you can get, plus some decent armor. Check out the Eye of Cthulhu guide and the Eater of Worlds guide for some great ways to make these fights go easier. Once you fight them a couple times and craft everything you can from the spoils, all the rest is more money for you. Another upside is that once have all the demonite you want and you're nowhere close to hardmode you can sell demonite for around 7 gold a stack.

Your payoff here is Demonite Ore that sells for each, a great profit indeed and well worth any ammunition and potions the player may have expended for the fight. Eater of Worlds also drops Shadow Scales worth a piece. If the player has spawned in a Crimson World, then they will fight the Brain of Cthulhu, who drops Crimtane Ore worth (4 ore make Crimtane Bar worth  and Tissue Samples worth  each. Crimtane Ore sells for a fair bit more than Demonite, so the player can get more profit if they have spawned in a Crimson World. The drops are randomized just like other enemy drops, so your mileage may vary. Even if you get horrific luck with drops, running bosses is well worth the time and effort and can be a lot more exciting than life on a potion farm.

By the time the player reaches high tier, they will have a defense of around 25. This statistic drastically reduces the damage the EoW and BoC do, and the player can easily destroy the two bosses. With lots of ammunition and good weapons (such as the Minishark or Night's Edge) they can make short work of both bosses, making more money than they could ever need. It is possible to defeat EoC eight or more times in one night, which sums up to.

Expected Profit: Varies

Selling Muskets
Another way to make money is selling guns (Musket). First, you need to create a new world, and then look for Shadow Orbs or Crimson Hearts, break them, and collect the items that drop. You can sell muskets for (Some muskets have more value, ). This method is very fast and you can even make more money by selling everything you get by killing the Eater of Worlds to get a lot of money.

The Destroyer
In hardmode, the player can fight The Destroyer and easily win if they have good enough gear (Mythril/Orichalcum armor is advised as a minimum, piercing weapons like the magic dagger are recommended). After crafting everything you need with his Souls of Might, you can just sell them. They sell for each, and you would normally get 20-40 of them per kill, which would sell for roughly. Besides, The Destroyer also drops 15-30 Hallowed Bars, which can be sold for per piece for a maximum of. However, these can be crafted into any type of Helmet, for an extra per 12 bars. It is possible to kill it up to 10 times in one night with the help of the Golden Shower and any of the starter hardmode sets, using the Headgear for extra magical damage. However, using the Paladin's Hammer the destroyer can be killed in less than 10 seconds if you find it while curled up, allowing massive profits to be made. Also, a magic harp (for endgame players) will be effective. A mythical heat ray with full spectre armor, a celestial stone/avenger emblem/sorcerer emblem with 2 other accessories all reforged to menacing, you can kill the destroyer in under 3 seconds. It is possible to save the summoning item for The Destroyer by putting it back into your inventory after it awakens.

Expected Profit: per run. In the mobile version, Gungnir still sells for, and souls of might still sell for. Making the destroyer extremely profitable. Earning at least per battle.
 * Note: Before 1.2.3, Gungnirs made from hallowed bars sell for per piece (more or less depending on modifier), and gave a large profit per run. However, its price now is only , lower than the cost of 12 hallowed bar
 * Note: Selling the hallowed bars is more profitable than selling excaliburs.


 * In 1.2.3 sell price of Souls of Might also has been lowered to, so you'll get less money now. To compensate that you can craft Light Discs from the bars and souls, which will almost double their value; you will also need some Souls of Light for that, but if you fight the boss in Hallowed biome you'll get more than enough.

Queen bee bashing
The queen bee becomes very easy to fight with hardmode weapons, especially end-game weapons like The Horseman's Blade, Terra Blade, etc. The QBs drop  per kill, and it is possible to kill one in about 20 seconds only with powerful enough stuff. An Unreal Tactical Shotgun with Crystal Bullets in full Shroomite Armor and max damage accessories (with damage modifiers) can kill the Queen Bee in 2-3 shots. Therefore, it is possible to make a minute, or  an hour, not counting the queen bee's numerous drops. Also, the Queen Bee doesn't need to be summoned during the day/night, and only needs to be summoned (not fought) in a jungle. In fine, Abeemination is rather easy to craft, as honey is dropped from the queen bee, stingers are dropped from the numerous hornets in the jungle, and honey blocks can be farmed renewably. However, you'll need to plunder beehives to get the non-renewable Hive.

With the addition of the Bee Armor set, Bee Wax itself sells for apiece. The Bee Headgear sells for at the cost of only 8 Bee Wax (or   total).

Wall of Flesh
Using post-Hardmode gear, you can farm the Wall of Flesh quickly and cheaply with a Flamethrower or a Golden Shower (Golden Shower is preferable since farming gel is harder than waiting for the Mana to recharge, barring access to a Slime Statue gel-farm.). Since you can summon him in day or night you can make more money than other bosses, unfortunately the amount of summons is based on guide respawns and voodoo demon spawns. Drops just for killing him, a Pwnhammer which sells for about , and a random other item which sells for.

Another trivial way to farm the Wall in early Hardmode, even before defeating any mechanical bosses, is by combining summons, such as the Spider Staff with the Spider armor, with a good Yoyo, such as the Amarok, and the Yoyo Bag. The Amarok is trivial to get in the Underground Snow biome and does tremendous damage to the Wall and its Hungries with a Yoyo Bag and its Frostburn debuff. While obtaining enough Spider Fangs to craft a Spider Staff and Spider armor is not so trivial, it is well worth the investment as the damage of five Spider minions makes the Underworld surprisingly safe. Red Devils can be a problem after at least one mechanical boss has been defeated, however.

Expected Profit: Varies (Estimated per day)

Golem
When you get the Picksaw from the Golem, you can move the altar located inside the jungle temple. You can make a box with Spiky Ball traps to easily farm the Golem. Sit back, and enjoy the loot!

Expected Profit: plus the item(s) he drops.

Pumpkin Moon
With full Nebula Armor, your choice of accessories, a Celestial emblem or Celestial Cuffs, and the weapon Last Prism, all with the most damaging modifiers, one can melt the waves of enemies. This works because the last prism is the highest dps weapon as of 1.3.0.4 and penetrates all enemies meaning you can hit multiple Mourning Wood and Pumpking. One does not need to worry about health and mana, because you kill the enemies fast enough each dropping approximately full health and mana each time you kill them. So as long as you are moving often and picking up Nebula boosters/hearts/mana you will not die. If you are having difficulties create a basic platform 2-3 screen widths long, with Campfires, Heart lanterns and Star in a Bottles along it every 3/4 screen width, this provides more health and mana regen as well as letting your Last Prism fire in a straight line. If you start at the beginning of night and are in wave 15 for at least half the event you should have 5-6 inventories full of items to sell (note the Spooky Wood has no sell value unless crafted into helms which sell for ea). This method can be done once every 24 minutes at the cost of 30 Pumpkin, 5 Ectoplasm and 10 Hallowed Bars to craft the Pumpkin Moon Medallion. This can also be done with an advanced trap arena if you want to acquire the money before the game is over.

Expected Profit: Varies per day.

Statue farming
The following statues spawn items or monsters (which don't drop coins, but will drop items), allowing you to make gold without even working for it:
 * Bomb Statue
 * Slime Statue
 * Jellyfish Statue
 * Skeleton Statue
 * Piranha Statue
 * Fish Statue
 * Shark Statue

Note: As of 1.3, Statue farming is much less time-efficient for generating money than before.

One of the easiest setups for a statue farm is to connect the statue to 1 or more 1 Second Timers (or a Crab Engine). Except for the bomb statue you should then either place the statue in a shallow layer of lava (recommended) or connect a few Dart Traps to kill the spawned monsters. Once you click the switch, all you have to do is stand still, or even return from time to time to collect the rewards. (Except for Bomb Statues, which will stop spawning when there are 3 Bombs, so you need to stay close to collect the bombs.)

In addition, using Bunny Statues and Fish Statues during a Blood Moon will spawn their corrupt counterparts, which rarely drop Bunny Hoods. The normal spawn limit for Statues is 3 mobs at a time, but when Goldfish and Bunnies change to their corrupt counterparts, they don't count towards the Statue's spawn limit, so you can have seemingly endless amounts of them on screen. This does not affect their actual spawn rate.

Expected profit (when using a Crab Engine and Lava and only one statue of the following ):
 * The Jellyfish Statue will yield about per hour, and will fill your inventory in about 13 minutes. This makes the Jellyfish statue probably the most effective one if you resell the items quickly.
 * The Bomb Statue will yield about per hour, and will fill your inventory in about 46 minutes.
 * The Skeleton Statue will yield about per hour, and will fill your inventory in about 18 minutes.
 * The Fish Statue will yield about  per hour and will fill your inventory in about 2 hours.
 * The Bat Statue will yield about  per hour and will fill your inventory in about 46 minutes.
 * The Piranha Statue will yield about  per hour and will fill your inventory in about 3 hours.
 * The Slime Statue will yield about  per hour and will fill your inventory in about 4.6 hours.
 * The Bunny Statue will yield about  per hour and will fill your inventory in about 12.5 hours.
 * The Bird Statue, Crab Statue will yield about per hour and will fill your inventory in about 6.4 days.
 * Sharks and mimics are slow to kill, limiting the efectiveness of such farms. These statues,howewer,can be used to farm ectoplasm (as both monsters have more than 100 health points),which sell for each. If one has already defeated Plantera and looted Lihzahrd Temple from traps,this method can yield about ,or even more if you're lucky.

The fastest statue to generate money is the Jellyfish Statue, but after 2 hours, items will start despawning. However, if you want the best AFK statue money generation in the game, hook up 3 Jellyfish Statue and lava (Below you), 3 Fish Statue and lava (On top of you) to a Bird Statue Engine or to a Crab Engine with only 3 blocks high of space between the two compartments so that you will be able to get the drops from both the Fish statues and the JellyFish statues. To maximize the selling speed if you are not AFK'ing, housing a Npc near your emplacement is strongly suggested for convenience. If you plan to AFK farm for more than 4 hours, it is better to farm Bombs, which start to despawn only after 7 hours. Bombs are optimal until you farm for 18 real life days, when banners from Fish/Bird/Crab start to become more profitable. At that point however, it would be better to turn off your computer and save electricity.

Killing Monsters
Once in Hardmode you can buy Gold Dust to craft items which will increase the amount of money monsters drop on death.

Slime Staff Farming
If you have a Lucky Coin and Slime Staff (Slime statues do drop Slime Staffs) you can farm for money very easily at the rate of about 10 Gold/Minute. Making full use of the NPC spawning mechanic, it is possible to make the speed exceed 1 platinum per minute. A simple way to apply the slime staff is to create a space in the Lihzarhd Temple where you can stand in a box in an open space with all of the Lihzarhds crowing below you. Then summon all of the slimes you can. The slimes hit very quickly and only do about 1 damage a hit, with each hit giving a chance to drop several gold coins due to the Lucky Coin. However, as the game mechanic works for piercing projectile (minions are counted as projectile, and as the slime won't vanish like common bullets after hitting one monster, it is considered as a piercing projectile) one monster will have 1/6 second's invulnerability time after it is hit by the slime, making the effect of adding more slimes not as much as someone may think. Also going into the Dungeon and looking for Paladins and Bone Lees but they are powerful enemies so this is not recommended.

Hallow Farm


Once you enter Hardmode, it may be a good idea to farm The Hallow. The best way to do this is to make an AFK Hallow Farm.

Building
The first thing to do is to clear out a flat area in The Hallow, which will help the spawn rate. Than create a pillar, at least 15 blocks high. The pillar should be made out of Hallow blocks or wood. After that, clear out two holes on both both sides of the pillar. These should be a thin layer, and not enough to destroy drops. This will kill the Unicorns. The next step is to make the part to kill the Pixies and Gastropods. It should have two box shaped parts, the first part thinner than the second, which will help catch the pixies in the trap. Some players may want to separate the parts with platforms. There should be Dart Traps or Super Dart Traps on both sides of the second section. These traps should be connected to a 1 Second Timer with wires. It is optional to have spear traps. This will kill the Pixies and Gastropods. The next step is to set up the player room. For maximum efficiency, the room should have a Water Candle, a Heart Lantern, a Campfire, Banners for the enemies, and a chest to store items. This room should be have doors to allow the player to exit, but not allow enemies in. The player should also have a minion.

Loot
You will make the most money off a 99 stack of Unicorn Horns, which will sell for  each. The second most money will be from Blessed Apples, which sell for each. The third most money will be from Fast Clocks and Megaphones, which sell for each. All the enemies also drop money.

Mimics
It's very effective to kill Mimics because they drop 10 Gold Coins by death, and you can sell the items they drop for even more money. And it's easy to kill them by using a continuously swinging sword with enough knockback to keep the Mimic at distance or killing them using a ranged weapon from a distance. If one has access to Gold Bullets or Flask of Gold,it will be wise to use them,as it will raise money dropped by Mimics even to 24 Gold Coins.

Hardmode Dungeon
A very fun and effective way to grind money is to gear up with endgame gear and farm the Hardmode Dungeon. After killing Plantera go in there and farm all the monsters you see. Armored Bones drop over ten silver each, and they are so common that you can easily rack up a lot of money fast. Also, sell the Ectoplasm and drops you don't need for even more money. In one hour, you might be able to get five platinum with water candles and battle potions and maybe even a lucky Blood Moon. Another way to use the dungeon for money-making is to use a farm. Lihzahrd Temple-type traps can prove to be very useful in this method, and will make fighting in the dungeon a lot safer.

Hardmode Spider Nest
An effective way to get money is in the Hardmode Spider Nest with a strong sword such as a Cutlass or Excalibur and a Water Candle and/or Battle Potion. Black Recluses drop directly, Spider Fangs which can be sold for  each, and Poison Staffs that sell for  each, which varies with modifiers that can change the sell value dramatically.

Expected Profit: Roughly  per minute

Handling money

 * Regularly deposit your money into a Chest, Piggy Bank, or Safe. This minimizes the loss of coins from Death, as death drops at least half the coins carried in the inventory.

What to keep
The following items can all be used to craft more profitable items, and should not be sold as-is or discarded:
 * Lesser Healing Potions and Lesser Mana Potions: Keep these around to eventually make full-sized Healing Potions and Mana Potions out of, then Restoration Potions if you can.
 * Clay: Crafts Pink Vases. They sell for each, which equals  per block.
 * Cobwebs: If you're saving up for Necro armor, keep in mind that you don't need too many of these -- a full set of the armor requires only 135 cobwebs. All the rest should be turned into Silk and sold for a net profit of per cobweb.
 * Goldfish: 2 Goldfish and 1 Bottled Water crafts the Fish Bowl, which sells for a whopping each.
 * Lens: 6 lenses (or 4 in mobile) allows you to craft a Suspicious Looking Eye and summon the Eye of Cthulhu for big cash rewards.
 * Glowing Mushroom: Glowing Mushrooms can be kept to make Lesser Healing Potions in to Healing Potions, as well as Lesser Mana Potions into Mana Potions; increasing value.
 * Jungle Spores: A stack of 99 Jungle Spores sells for, but turning these into 12 Jungle Hats will get you.
 * Cactus: sells for but crafting into  Cactus Sword which sells for   and requires only ten cactus and that is   profit (depending on modifier).

What to discard
These things are going to clog your inventory to no end, and are almost impossible to make money off of. If your inventory is full and you're deciding what items to take home and sell, go ahead and trash these:
 * Dirt Blocks: Useful for growing some plants and handy as a plentiful building material, but will never be more than that. You can always get more.
 * Mud Blocks: Mud is used to grow mushroom grass or Chlorophyte, both of which are valuable and can be combined to make high-selling bars, or as a building material. Mud can be crafted from dirt when standing in or near water.
 * Wooden Arrows: Very common in pots and chests, only pick them up if you'll use them as ammo, to craft better arrows, or you've got nothing more valuable to keep in that inventory slot.
 * Shuriken and Throwing Knives: You'll find a lot of these in chests underground, but in such small amounts that they're not worth carrying. If you've got a decent ranged weapon you won't see much benefit from carrying these.

What to sell
These raw items are worth selling as-is. When your inventory is full and you need to choose, try to keep these around and toss something else:
 * Accessories and Weapons: The less you use something, the less likely you are to use it in the future. Most accessories will sell for great amounts of coins and will not stack, so go ahead and sell them. As stated before, if you can find one thing you can find ten more. If you've got multiple copies of an accessory then you'll probably find many more copies in the future, so don't worry about something being gone forever. Possible exceptions are swords required to craft the Night's Edge, which you may want to keep duplicates of so you'll still have use of them even after sacrificing them to craft it, and accessories which can be upgraded using the Tinkerer's Workshop, such as the Tiger Climbing Gear, which can then be upgraded to the very useful Master Ninja Gear later in the game.
 * Ores: Excess ores can be sold once you're kitted out and your house is decorated from top to bottom. It may however, still be a good idea to keep your gold, copper, and iron ores because you will need these for hardmode items later on. Meteorite ore should be crafted to bars before selling for better profit. Note that iron/lead bars are required to craft hardmode boss summoning items.
 * Collecting and selling Crystal Shards, which you can find in the underground hallow or by simply killing demons in the underworld. They are easy to collect and sell for lots of money - a hundred being worth - meaning a full stack can net you just over 1 platinum.

File duplication
When a character (or world) is created, it is saved as a file on your computer. This means that it can be copied like any other file. The default directory for such files are, though this may change with OS. Characters are stored as .plr files; a character called "Manbearpig" will be saved as "Manbearpig.plr". If this file is copied (into "Manbearpig2.plr", for example) the in-game character selection menu will feature two characters named "Manbearpig". (Note that there is no need to copy "Manbearpig.plr.bak". Also note that the order of the .plr files in the Players-folder is representative for the in-game character list.)

The copy will feature all items held and worn by the original, allowing the player to duplicate money and items by repeatedly copying Manbearpig.plr and deposit the copies' inventories in a storage item in-game. Creating money like this makes it increase exponentially: if you start with and copy it 31 times, you will have a little more than  (1*2=2 (one copy) → 230=1073741824 copper coins = 1073 platinum coins).

Copied character files can afterwards be deleted with no issues arising, though you'll also have to delete each copy's respective .plr.bak file and folder. Though arguably being somewhat cumbersome, this method is convenient as it requires no third-party software.

Mods
External third-party programs (mods) such as TerrariViewer and TEdit can be used to alter character or world files. This means they can be used to make money. For example, the former can be used to fill a character's inventory with coins, while the latter can be used to fill a chest.

Cheating
Set your world to "read-only" while you have all your coins in a chest, then load the world. Take the coins, and exit. Set "read-only" off and play again. The coins you took while the world was "read-only" will be in the chest, and you can take them out. If you had, say, about 50 gold, you could get a platinum, and, if you do it again, you can get 2 platinum. And you can do this method whenever needed to get coins back.

Also, place a door next to a cliff. To the left and one above the door (have it opened), place a coin. Stand back and face the door. Close the door, and when the falling coin block passes the door, open it again. You should pick up two coins, unless you were too slow. In this case, try again.

Magic Mirror Duplication
Note: Doesn't work if you're the host. Note: Items have a chance of disappearing.

First, in your inventory highlight the coin(s) you want to duplicate. Then, exit out of your inventory. After that has been done, you use the magic mirror and while the screen turns black, you pull up your inventory and pick up the coin(s).

Misc tips
Another quite easy way is to make another world, go to the Corruption, locate a Shadow Orb and then use a hammer to break the Shadow Orbs, selling the items you get from them (which is optional). Once you have broken 3 Shadow Orbs the Eater Of Worlds will spawn. Kill him and collect everything. Turn the Demonite Ore into bars, then sell them. One stack of 99 Demonite Bars can sell for 31 Gold Coins. Each world spawns with about 6-11 Shadow Orbs, therefore spawning about 3 Eater Of Worlds, which, in total, would drop about one or two Platinum Coins and a few Gold Coins.

In hardmode, traveling to the Underground Hallow and collecting as many Crystal Shards as possible is an extremely efficient way to acquire large amounts of money, as one full stack (consisting of 999 shards) sells for almost 1 platinum and 60 gold coins (16 silver coins per shard), plus it doesn't require any specific early investment or preparation (other than reaching Hardmode itself). Crystals are abundant, easy to locate and mine, and respawn. Killing enemies that appear as you run around the Underground Hallow will let you collect even more coins.