The nice folks at recently reported on widespread sneaky tricks employed by credit card companies. (Our own credit expert, Dayana Yochim, also recently wrote about "Stupid Credit Tricks.") Here are some of the tricks they mentioned. Be familiar with and ready for them, so that you don't end up forking over more than you need to.

  • Universal default penalties. If you're late paying any bill, your card companies may get wind of it via your credit report and hike your interest rate accordingly. It seems that 44% of cards have these policies in place.
  • Bait-and-switch card offers. You may be sent info on a card with a terrific low rate. But if you don't qualify for it, you'll be sent a card with a higher rate.
  • Endangered grace periods. Cards traditionally gave you about 30 days in which to pay your bill before interest was added to it. These grace periods now average 23 days, with some cards having no grace period at all.
  • Fees, fees, fees. Some card companies have the gall to sock you with "inactivity" fees of as much as $15 if you haven't used your card lately. Consider it a nudge to get out there and rack up some big expenses, on which they hope to soon charge you interest. Meanwhile, pay your bill late, and you may be slapped with a late payment fee of up to $40. Ouch. Companies cited as "steep chargers" include Providian (NYSE:PVN), Bank of America (NYSE:BAC), and MBNA (NYSE:KRB). On top of that, exceed your charging limit and you'll be fined $25 to $39. notes, "Cruelly, a $39 late fee can then trigger a $39 over-limit fee."

This is all fairly alarming and depressing, but you can make lemonade out of these lemons. Be an informed card user and you can let your cards benefit you financially, instead of it being the other way around.

Learn about the credit card industry and how to get out of debt in our Credit Center. And read about all things credit-related on our Consumer Credit / Credit Cards discussion board.

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