I know many people will take advantage of zero-interest rate offers from credit cards. If you're not carful, those offers can be costly. In this reader story at Get Rich Slowly
, a reader describes how she took advantage of a Barclays credit card offer which allowed her to purchase a $1,290 iMac and pay it off over a 12-month period without paying any interest. She had thought she had paid it off, but due to how the bank credited her payments, she didn't completely pay it off, and it cost her a $247 interest charge.