Introduction. Thousands of years ago people had no system of money as we know it today.They used the barter system of trading.Barter is the exchange of a good or service for another good or service: e.g. a bag of rice for a bag of beans. . CashCoins and notes are exchanged for goods and services.Cash is normally used for most small purchases, such as food, newspapers and bus tickets.Carrying a lot of cash around is quite risky as it can be lost or stolen..