Chestshop allows players to buy/sell when their offline tho, hoppers and comparitor shops are too confusing for some people.

If it is added then there should be a charge for every shop created

Maybe adding the ChestShop plugin so players can create little "malls" to sell their unwanted stuff at a custom price!

Also a mall at spawn where players can rent plots for a certain amount of time for a price! This will help their shops be used more!        Hope you Have More Ideas!