So my suggestion is simple. Add auction house to all the servers like it already exists on factions and skyblock. Instead of running one auction at a time by one player it would be better and easier to have the auction house so anyone can sell whatever they want without having to wait the running auction to be over and it will also reduce the spam in chat.
So you do /ah and the pop up comes and you can sell/buy whatever you want according to categories? Seems all right.
you just do /ah and then it displays everything that every player sells at that moment and you do /ah sell (price) to add whatever you want to sell to other players in it.
Plugin link: https://www.spigotmc.org/resources/auction-house-1-7-1-11.6050/ Something it doesn't have is a search or category option and I don't believe you can change this. If you can, it's fairly easy to write a few lines to create those options.
