Can you add an exchange plugin that will reduce scam??? You can do trade with a player just do /trade [Username]
Eh, not support. It's not too necessary; but I guess it wouldn't hurt. Players need to understand that not everyone is trustworthy. Screenshot agreements, have a mod watch the trade, and be prepared just in case a scam occurs. It's really that simple.
You can implement tradeshops in banner shops! You just have to learn how to type the tradeshop's sign... Which I'd help with but I don't know how... :/ Just put the chest down, the sign above it, and the respective banner above that!
Wait for chestshop to be fixed. In the meantime take careful screenshots of people agreeing to trades.
We used to have one, but you could dupe with it, so it was removed. Just use chestshops, or have a moderator moderate the trade, or just record it to avoid scams.