Although the crucial feature of money is its acceptance as the means of payment or medium of exchange, money has three other functions. It serves as a unit of account, as a store of value, and as a standard of deferred payment. We discuss each of the four functions of money in turn.
Money, the medium of exchange, is used in one - half of almost all exchange. Workers exchange labor services for money. People buy or sell goods in exchange for money. We accept money not to consume it directly but because it can subsequently be used to buy things we do wish to consume. Money is the medium through which people exchange goods and services.
A barter economy has no medium of exchange. Goods are traded directly or swapped for other goods.
In a barter economy, the seller and the buyer each must want something the other has to offer. Each person is simultaneously a seller and a buyer. In order to see a film, you must hand over in exchange a good or service that the cinema manager wants. There has to be a double coincidence of wants. You have to find a cinema where the manager wants what you have to offer in exchange.
Trading is very expensive in a barter economy. People must spend a lot of time and effort finding others with whom they can make mutually satisfactory swaps. Since time and efforts are scarce resources, a barter economy is wasteful. The use of money – any commodity generally accepted in payment for goods, services, and debts – makes the trading process simpler and more efficient.