Tom's Trading Network
This mod simplifies trading between players in Minecraft by providing convenient tools for item exchange. The project is currently in active development but already offers useful features.
The main element of the mod is the vending machine, which allows you to set up simple trades. You can program one item exchange and configure sides for input and output of goods.
A special feature of the vending machine is that it functions even in protected areas (claimed chunks) without requiring special interaction permissions. In the configuration interface, additional options are available when right-clicking on item stacks.