Coins

Coins are Terraria's unit of currency. They are primarily used for NPC transactions, though other players may also accept them as payment in multiplayer.

Types of Coins
There are four types of Coins in Terraria: Copper, Silver, Gold and Platinum Coins. Each is worth 100 of the Coin of the previous rank. One Platinum Coin is worth a million Copper Coins.

Obtaining Coins
Coins can be acquired by killing monsters, breaking pots, or trading with NPCs (or other players). Even though the Coins are "Copper", "Silver" or "Gold", it is impossible to craft them from Ore, Bars, or any other item in general (apart from a different rank of Coins).

Coin Harvest Technique
An easy way to acquire Coins is to harvest Sand Blocks, craft the sand into Glass then Bottles, and then sell those to an NPC for about 20 Silver per 99. This works well because sand is especially easy to harvest. This technique makes Deserts a virtual Coin mine.

Storage
Like other items, Coins can be stored in Chests and Piggy Banks. Be careful though, as Goblin Thieves can steal them from these containers. It is recommended to always store them, as it will prevent them from being dropped upon death, the penalty of which is dropping half of your carried coins (rounded up).

Inside the inventory, Coins have their own special set of 4 slots on the right of the inventory grid.