It's something that most people think they don't have enough of, and yet it's only a piece of linen and cotton material just 6.14 inches by 2.61 inches or a disc of non-precious metal. It lasts from one year to 30 years, depending on whether it's currency or coin. What is it? It's money! But why do we need money? What function does it serve? Is the economy better because we have it?