most of us have been brought up in an "exchange-value" society. we make everyday decisions from the perspective that the value of an item is determined by what it can be exchanged for. this is in contrast to use-value -- what an item is directly or immediately useful for. for example, the use-value of an apple is high (it can be eaten), but its exchange-value is low (it spoils); alternatively, gold has a low use-value (it doesn't provide sustenance), but it has a high exchange-value (it's rare and easy-to-store).