Money is a tool we use to trade value with each other. Instead of swapping your apples for someone's oranges, we use coins and bills that everyone agrees have value. Money lets you save up for things you want, pay for services, and plan for the future. There are three main things money does: it's a medium of exchange (you use it to buy things), a store of value (you can save it), and a unit of account (you can measure how much something is worth).