I think most games don't really explore it, because money really doesn't make much of a sense in most games. Moneys main function in reality is to barter for thinks that are necessary for your life like food, cloth, rent and so on. A lot of things most people don't want to have in a game, because it tends to be tedious and not very fun. So you can either don't implement them and risk parties getting filthy rich or you devise ways to spend money (usually equipment stepstones), that always tend to be a bit obvious and tacked on.
The immersion breaking part isn't the money itself, but that the protagonist and his party are the only ones, who don't actually need any to survive, because they are not really alive.