I apologize if this has been discussed before, but I cannot seem to find a solution. I have tried a variety of plugins to balance villager trades, but there always seem to be those few players that find a villager that makes it effortless to become rich. They do the trade, go to the server shop and sell - repeat. Since we sell everything in the game in an adminshop, and also allow players to have their own shops, we really don't need villager shops. They are unpredictable, and really messes with the economy. I'd really like to be able to just cancel it altogether, but obviously still have them in game.
Use NoNpcTrade, its a plugin that you can configure so all npc's including modded npc, will not have anything to trade!