Compound interest is how your money makes money -- and it can make you rich.
CNBC Select defines compound interest, how it works and ways to take advantage of it if you're looking for a new credit card or somewhere to stash your cash.
Why do people invest? It's not just to get a tax break from contributions to a 401(k). The ultimate reason is that we want our money to grow for the future. The way that money grows, and the biggest ...