The credit card industry is a competitive one; all you have to do to see that is open your mailbox. For many consumers, pre-approved credit card applications can be found every week in the mail, often accompanied by offers to let you transfer an existing balance from another credit card at a low interest rate. Sometimes these rates, known as "teaser" rates, can run as low as 0%, which can make applying for one of these cards rather tempting. Be careful, though. The fine print in the terms of agreement on those cards could hide some very expensive surprises.

Here are some things to watch out for in the fine print when you apply for a card with a low-interest introductory offer: