Money makes the world go around. Economies rely on the exchange of money for products and services. Economists define money, where it comes from, and what it's worth. Here are the multifaceted characteristics of money. Before the development of a medium of exchange—that is, money—people would barter to obtain the goods and services they needed. Two individuals, each possessing some goods the other wanted, would enter into an agreement to trade.

Early forms of bartering, however, do not provide the transferability and divisibility that makes trading efficient. For instance, if someone has cows but needs bananas, they must find someone who not only has bananas but also the desire for meat. What if that individual finds someone who has the need for meat but no bananas and can only offer potatoes? To get meat, that person must find someone who has bananas and wants potatoes, and so on.