RPCurrency

RP Currency is basically a player-run shop system for Minecraft. It lets you turn chests into custom trade shops where you can set up your own deals, name your shop, and sell items with prices you set

Shop owners can configure trades through a setup screen, and other players get a customer interface when they interact with the chest. To open either trade screen you have to hold SHIFT+right-click.

In short, it makes buying and selling between players way smoother and way more fun. It also adds craftable coins and a coin purse!