Hi all back with another problem I cant seem to find the answer too. I want to create a custom merchant who pays 400 gold for human hearts, 500 gold for briar hearts and 600 gold for Deadra Hearts. I only wont my custom merchant to offer this price and all other merchant to keep the vanilla default prices for the hearts. Does anyone know how I can do this?

Take a look at the Speech perk that reduces prices across the board(Haggling or Allure), and then make a similar perk that makes the merchant pay more for specific items. You don't have to edit the tree, it can be a "passive" perk added to the player.

Ok I will try that