Money is any good that is widely used and accepted as a medium of exchange, a measure of value, and a store of value. It functions as a medium of exchange by allowing for the purchase and sale of goods and services. As a measure of value, money can be used to determine the worth of goods and services. It also serves as a store of value by maintaining purchasing power over time. There are different forms of money including coins issued by the government that are made from metals and have designated values, as well as paper money known as notes that are printed on paper and issued by a central bank.