What is money? Money is any good that is widely used and accepted in transactions involving the transfer of goods and services from one person to another. Economists differentiate among three different types of money: commodity money, fiat money, and bank money. Commodity money is a good whose value serves as the value of money. Gold coins are an example of commodity money. In most countries, commodity money has been replaced with fiat money. Fiat money is a good, the value of which is less than the value it represents as money. Dollar bills are an example of fiat money because their value as slips of printed paper is less than their value as money. Bank money consists of the book credit that banks extend to their depositors. Transactions made using checks drawn on deposits held at banks involve the use of bank money.