This year's Christmas gifts could be next year's financial disaster.
Special financing offers—"Pay nothing until March 2015," "$0 down, 0% interest" and the like—are a common pitch this time of year, showing up for purchases of everything from electronics and furniture to toys and clothes.
In fact, 70 percent of major retailers offer a financing option, with more jumping on the bandwagon every year, according to a study from CardHub.com. Kohl's, Dillard's and True Value are among the brands that have expanded or added financing this year, the site reports.
Depending on the deal, consumers might make monthly installments over a set period or pay at their discretion (with a low monthly minimum) until the lump sum comes due.
But credit and debt experts say financing deals can be a ticking time bomb.
"We think these offers are on [Santa's] naughty list, no matter how stores present it to consumers," said Odysseas Papadimitriou, CEO of CardHub.com. By his estimate, financing can be 27.5 times as expensive as using a credit card.
John Ulzheimer, credit expert at CreditSesame.com, minced fewer words. "I can't stand those offers," he said. "I hate them."
(Read more: Affording a no-interest credit card offer)
Terms and conditions get ugly very fast if consumers miss a payment or fail to pay the balance in full within the promotional period. If that happens, you'll owe interest on more than just the remaining balance, Papadimitriou said.
Half of retailers' policies apply interest retroactively from the date of purchase to the entire balance, often at rates that top 20 percent. That's enough to counterbalance any holiday sales or discounts, and can add a month or two to the time it takes to pay off the debt.
"It's completely counterintuitive, and people don't expect that," Papadimitriou said.