When we no longer agree that the paper money, no longer backed by equivalent precious metal (no modern currency is), has become useless, we have the situation in Zimbabwe and other African nations and until recently some Eastern European currencies. Then the population moves to a barter economy, with all its problems. Barter can really only succeed within a physically restrictive area- when local goods can be traded. The development of money responded to the need to trade away from home, and is culturally acceptable by mutual agreement anywhere. Barter isn't, but in Zimbabwe at the moment I guess the rich guy is the one with a few eggs from his hens to trade for some fresh vegetables, not a guy with heaps of money in his pocket, or the bank- with nothing to eat in his cupboard.
