TULSA, Oklahoma - There are a lot of options for shoppers who are out looking for holiday gifts, but the website CardHub says there is a dark side to holiday financing.

Larry Rosebure is a counselor for Christian Credit Counseling in Tulsa; he said Christmas shoppers need to pay attention to deferred interest deals.

“Very simply, read the fine print," he said.

Deferred interest plans are typically marketed as offering zero percent introductory terms, which can save you money, especially on big purchases.

But they come with a catch that makes them different from ordinary zero percent credit cards.

"Most retailers, if you don't pay it off in full by the expiration date, are tracking that interest and accruing it. And if you don't pay it in full, they will apply it to your account," Rosebure explained.

If you have an unpaid balance of even $1 at the end of the introductory period, or, in some cases, if you miss a single payment, interest will retroactively apply to your entire original purchase amount.

"We've seen people really startled with interest that was clocking at 20, 22 percent," said Rosebure.

Cardhub found 73 percent of major retailers offer financing options for customers. Of those major retailers, 47 percent offer a deferred interest plan.

They aren't just offered during the holidays, but Rosebure said deadlines can easily sneak up on Christmas shoppers a few months down the road.

"A not so welcome springtime surprise," he said.

Deferred interest can be a good way to pay for big purchases over time, just as long as you're not surprised later.

You can get more of CardHub's deferred interest report on their website, including the big retailers with the least transparent deferred interest financing plans.