Try to imagine an economy without money. Without money, it would be almost impossible to carry out the usual day to day business of life. For instance, if you wanted to buy a hamburger without cash, you would have to give the restaurant something else in return. Perhaps you could wash the dishes, or sweep the floor. Either way, the ability to pay for goods and services with money greatly simplifies consumer life and eliminates the necessity of bartering goods and services for other goods and services.
What exactly does money do? Sure, you can buy things with it and save it, but how does it function within the economy? There are four basic functions of money:
The most obvious function of money is as a medium of exchange. When you hand the waiter a five-dollar bill in exchange for your hamburger, you are using money as a medium of exchange. You might have a hard time paying for your hamburger with five dollars worth of apples, but if you did, the apples would serve as a medium of exchange as well. To simplify, a medium of exchange is something that buyers give to sellers in exchange for goods and services. Perhaps money's most compelling advantage is that it is a commonly recognized and universally accepted medium of exchange. This allows anyone with money to walk into any restaurant with the confidence that the waiter or clerk will take your cash in exchange for goods or services. This would likely not be the case with a basket full of apples.
The second function of money, as a unit of account, is rather obvious, but you may never have considered it before. When you walk into a restaurant, the menu tells you that a hamburger costs $5 and a steak costs $15. You know what this means and are able to compare these prices. If, on the other hand, apples and oranges were used as units of account, comparison between the costs of goods and services would be much more difficult. Imagine trying to determine what costs more, a hamburger costing 25 apples or a steak costing 30 oranges. As a unit of account, money serves as the common base of comparison that people use to present prices and record debts. Without a common unit of account, these tasks would be much more difficult.
The third function of money, as a store of value, is one that we all know well. When you work, you are paid a wage. The portion of that wage that you do not spend gets saved. By saving money, you are able to spend some now and some later. In this way, money serves as a store of value, allowing you to trade current consumption for future consumption. Imagine if you were paid in bananas. Any bananas that you did not eat or trade immediately would rot, rendering you unable to enjoy the fruits of your labor at a later time.
The fourth and final function of money, as a means of liquidity, is important for an economy to move beyond a simple system of bartering. Imagine that you have 30 apples, and you really want a steak. You walk to the local restaurant and ask the waiter if you can trade 30 apples for a steak. He informs you that they have plenty of apples, but could use some oranges. Frustrated and hungry, you walk out of the restaurant. In this example, apples lacked liquidity since they could not easily be traded for what you wanted. Liquidity describes the ease with which an item can be traded for something that you want, or into the common currency within an economy. Money is the most liquid asset because it is universally recognized and accepted as the common currency. In this way, money gives consumers the freedom to trade goods and services easily without having to barter.
Money comes in a number of different forms. In the preceding section, we saw apples and oranges used as money. When something with intrinsic value, like precious metals, is used as money, it is called commodity money. It is interesting to think about the enormous variety of goods that can serve as commodity money. Basically, anything that can fulfill the four functions of money, to so some degree, can be used as commodity money.
Barter economies depend on commodity money. When something lacking intrinsic value is used as money, it is called fiat money. This system only works if a government backs the fiat money and regulates its production. In most countries, the cash or currency is a form of fiat money. The advent of fiat money is a great convenience in many ways-- imagine trying to carry a week's pay in apples and oranges.