One call to your credit-card company could win you a lower interest rate or get you out of a penalty fee.

So before you switch to another credit card in search of a lower interest rate, first call your current issuer to see what it's willing to do for you. Assuming you've been a good customer, the issuer might agree to waive fees or lower your interest rate to retain your business. Plus, the longer you stay with a particular card issuer and maintain a good record of payments, the higher your credit score will be. In our survey, readers who called their card issuers to negotiate a lower interest rate succeeded more than 50 percent of the time. And 79 percent of readers who tried were successful in persuading their card issuer to waive a penalty fee.

In another recent survey the Consumer Reports National Research Center found that 57 percent of people who bargained with their banks or card issuers over fees saved $50 or more.