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Goods and services are exchanged for money and money is used to obtain other goods and services. Thus money is a medium of exchange. In many countries, the monetary system has been built on a base of precious metals such as gold or silver, but cowries heels, salt and many other things can be, and have been, used as money. Although a primitive trading economy can be carried on without the use of money, history suggests that at an early stage of development, something – and it does not really matter what that “something” is – will begin to perform the various functions of money. Indeed, it is true, that an economy cannot progress at the primitive stage called the barter system.
2. The Barter System
It is convenient, to explain the need for the introduction of a form of money, by looking at the situation which precedes it. The situation is usually known as a system of barter. Under the barter system trade is difficult, but not impossible. The first problem is the “double co-incidence of wants”.
It means that not only must one man have goods which a second man wants but also that the second man must have goods which the first is willing to take in exchange. Let us take a simple situation. A farmer growing, for example, wheat, might wish to introduce some variety into his diet and so decides to obtain some fish. He therefore finds a fisherman and wants to exchange some of his fish. If the farmer is lucky, he will find a fisherman who not only has some fish he willing to sell, but also requires some wheat. In this event, exchange can take place with little trouble. But supposing that although the fisherman has fish available to sell, he wishes some wool, rather than wheat. In that case the farmer will first have to find a third person who has wool and wishes to take wheat in exchange. Thus he would have to exchange his wheat for wool before he could obtain the fish which he really wants.

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