Paying down credit card debt is one of the smartest things you can do with extra cash.

For most of us, it's usually smarter than putting extra money into CDs or retirement plans.

That's because the interest rate credit cards charge is usually higher -- often a lot higher -- than we can make with any investment.

You simply can't earn enough, even with a mutual fund that returns 7% or 8% a year, to cover the 18% or more you're probably paying on your credit card debt.

That's why it's hard to save and get ahead while carrying any kind of balance on your credit cards.

Our credit card calculators can help you figure out the quickest way to pay off one credit card or a bunch of credit cards.

There is one important exception to this rule.

If you don't have enough readily available savings to cover six to nine months of living expenses, then any extra cash should be set aside for emergency savings regardless of the return.

If you have some extra cash to invest but don't have any credit card debt, good for you. There are a number of ways you can invest that money and watch it grow.

Here are some other ways you can use $1,000 to make your financial future more secure.