Coins

Coins are the currency of Terraria.

Obtaining coins
Players can obtain coins by killing monsters, destroying pots, finding them in chests or selling items to Vendors and sometimes you might be able to get some through a glitch (being given the option to turn a coin into 100 of the coin below). With coins you can buy things from the Vendors. A stack of up to 100 of any single type of coin takes up one inventory slot. However, there are reserved slots for coins, on the far right side of the inventory that may be used instead.

Coin types
Coins come in different types:

Curiously, Platinum is not a mineral that can be found in ore/bar form, making it a mystery as to where the coins come from. Platinum is the most valuable coin available.

Crafting and value
Coins can be crafted to and from other coin types. It takes 100 coins to upgrade, and you get 100 coins when downgrading
 * 100 Copper equals 1 Silver
 * 100 Silver equals 1 Gold
 * 100 Gold equals 1 Platinum
 * 1 Gold equals 10,000 Copper
 * 1 Platinum equals 1,000,000 Copper
 * 1 Platinum equals 10,000 Silver

Death penalty
Upon death, half of all the stacks you have of coins in your inventory will be dropped. For example, if you have 1 Gold coin in one stack, you will lose it, but if you have 12 coins you will lose 6. You will still lose the coins if they are in regular inventory slots. They can be recovered if you are able to find the location where you died.

You do not lose any of the coins in your inventory when you die as a result of self-thrown explosives.

Storage
Coins have their own storage slot but can also be stored in the normal inventory like anything else. Coins can be stored in a Chest, Safe or in a Piggy Bank. Coins placed in any stationary container will not be lost when you die. It is advisable to place all your coins in a Chest, Safe or Piggy Bank everytime you return to your home or before fighting a boss.

Bugs

 * It is possible to keep one stack of coins on death by "holding" it with your mouse arrow right before you die, but as of the patch 1.1.1, mouse items drop normally on Hardcore and Mediumcore characters.

Trivia
Coins are one of the few things that can be sold and bought for the same price; because of this, you can make it look like you have an abnormally large amount of money above your head, but the look is purely aesthetic. To do this trick, you must simply sell the coin and rebuy it from the same slot quickly.