Fargo's Mod/Mutant's Discount Card

The Mutant's Discount Card is a consumable item dropped by the Wall of Flesh in. On use, it reduces the prices of all of the items sold by the NPC by 20%. The Mutant's Discount Card will only drop if the player has not used a Mutant's Discount Card in the world previously, and will have no effect if used in a world that has already used one.