PHILADELPHIA (CBS) – Are you planning on making any big purchases soon?

Those interest-free offers we see advertised from time to time can certainly save you a lot of money, but you better take along a
magnifying glass when you shop. Not paying attention to the fine print can cost you big.

There was no question Justin Miller has a big comfortable bed.

“The bed is great. We love the bed,” said Miller.

It’s how he financed the Tempur-Pedic mattress that’s keeping him up at night.

“We could obviously pay up front or they had this special deal,” said Miller.

The deal was a Citibank credit plan offering 12 months interest free on their $5,600 purchase.

“No interest for a year, is a great deal. It sounded good,” said Miller.

But after he made what he thought was his 12th and final payment, along came a bill from Citibank for $1,300 including a year’s worth of 25 percent.

“I thought this is crazy. Either this is some kind of joke, or some kind of scam,” said Miller.

It turns out Miller’s one year interest-free deal expired on December 2nd, 2010. It says so in this tiny type on his monthly statement.

But what Miller considered to be his final payment was due on December 6th, four days later!

“So, the statement due date was different from what they call the plan due date,” said Miller.

Miller believes that’s intentional, a trap to fool customers into making their last payment after the interest free deal expires.

“You should always read the fine print, know the terms and conditions,” said Anita Brown with Consumer Credit Counseling Service.

Brown suggests paying the balance over 11 months.

“Just to be on the safe side, and make those payments over those 11 months so that you’ll be sure to pay that off in the 12 month promotional period,” said Brown.

Citibank says, “The terms of the deal are clearly explained in the seven-page contract”.

Justin Miller doesn’t think so. He’s telling his story on Facebook and hoping to get the last word.

“I’m never going to do business with Citibank again,” said Miller.

Banks rarely go out of their way to notify you that your interest free deal is about to expire.

Miller managed to convince Citibank to “reduce” that penalty interest charge from $1,300 to $650. When asked what happened here, Citibank refused to discuss the specifics, but low and behold they agreed waive the entire interest charge.

Watch the video…

Reported by Jim Donovan, CBS 3

Watch & Listen LIVE