"Gold sink is an economic process by which a video game's ingame currency ('gold'), or any item that can be valued against it, is removed. This process is comparable to financial repression in real economies. Most commonly the genres are role-playing game or massively multiplayer online game. The term is comparable to timesink, but usually used in reference to game design and balance, commonly to reduce inflation when commodities and wealth are continuously fed to players through sources such as Gold taps; such as quests, looting monsters, or minigames."
https://en.wikipedia.org/wiki/Gold_sink