Money

Money allows for the separation of selling something for money, keeping that money for a while before buying something else with that money. With either barter or some other type of direct exchange, gift giving or balanced reciprocity that exchange is often one item for another there is, neither a separation in time or space. Even if there is a separation there is a corresponding responsibility is such that one of an equivalent exchange in the future is expected. Money allows an element of freedom as an added dimension to the exchange process.  But this freedom expressed through a separation in the selling and buying has a built in element of uncertainty. Either hoarding of failure to find a buyer means a break in the process. Karl Polanyi