Tempted by those "Buy now, don't pay until 2012!" promotions? They can be a great deal. But there's a catch. Chris Olsen magnifies the fine print that could cost you big.

Getting something now, and putting off paying for a whole year, sure sounds tempting

But "no payments and no interest" isn't free, as many consumers have discovered the hard way.

"I got dinged really hard after the time ran out," one disappointed shopper told CTV News.

The plans start with an administration fee -- $100 is fairly typical. You pay that up front along with all taxes.

Then, with most plans, interest begins to accumulate from the day you bought it. And it can really stack up. For example, after 18 months the interest on a $1,000 television is $450. If you pay in full --$1,000 -- the interest disappears. But if you pay late or don't pay it off completely you are on the hook for all that interest.

Most consumers wish that information wasn't buried in the fine print.

Even paying nine-tenths of the money won't save you from all that interest, so marketing expert Lindsay Meredith recommends you start saving now.

"You've got to save ahead, and if you can't save ahead for heaven's sake get a line of credit," he said. "But don't use the line of credit it's an insurance policy for you."

Meredith points to administration fees, selling you extras like extended warranties, and money made off those who miss the due date as the only way those promotions can be profitable.

"No one can afford to give you 12 months or 18 months free interest," he said.

He says saving up for a year or two, instead of getting it now, means you'll buy a better product for less and protect yourself from an uncertain future.

One final complication: in most cases you can't just walk in on your due date to pay off your bill. Plan to pay a month in advance -- so there's no chance you'll get dinged --and be aware the companies often demand cash, debit card or direct payment. They won't let you use another credit card to pay the bill.

With a report from CTV British Columbia's Chris Olsen