Maybe you've heard some of our credit card advice before. Maybe you've ignored much of it, thinking it won't save you all that much. Think again.

Let's look at just one bit of advice. In our Get Out of Debt nook, we recommend that you call your credit card company and ask for a lower interest rate:

"Let your creditors know your situation. Tell them that if you are unable to renegotiate terms, then you have no other recourse except to declare bankruptcy. Ask for a new and lower repayment schedule, request a lower interest rate, and appeal to their desire to receive payment. Faced with the prospect that you may resort to such a drastic step, creditors will do what they can to protect themselves against a total loss."

With credit card companies, let them know that you're ready to switch to another card. And actually be ready to do so. (We can help you choose a better card; perhaps you might even like our Fool Credit Card.) Many of us hold cards that are charging us 20%, 25%, even 30% or more per year in interest. If you have a respectable credit record, you should be able to get your rate down into the mid- to low teens, at least.

Does this kind of phone call work? It actually does, quite often. In a Massachusetts Public Interest Research Group (MASSPIRG) study, "More than half of consumers who called their credit card company to complain about their high annual interest rates were successful in reducing those rates by an average of one-third." It helps to have held the card in question for a long time and to have a decent credit rating. (Check your credit record -- to see how you stack up and to find any costly errors. Chances are good that your report contains errors.)

If you carry a balance on your card and your rate is cut by a third, you can save hundreds of dollars per year and thousands of dollars over a longer time. And you may be able to reap this reward simply by placing a five-minute phone call. so what are you waiting for?

Learn more in these articles about the surprisingly interesting world of credit cards:

You can learn even more, including how to get out of debt, in our Credit Center. And read about all things credit-related on our Consumer Credit/Credit Card discussion board.

Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article.