Luz Cottes charges holiday gifts for her son and daughter on her Macy's store credit card. The New Castle, Del., resident knows she can't pay it off immediately. She knows the card has a high interest rate. But she also knows that she can instantly save $20.

"During the holiday, I charge and charge, and the next holiday I'm still in debt," Cottes said.

Such examples of quick-rebate, long-term debt are becoming more common as flashy store credit cards are offering more tempting perks, particularly during the holiday season. JCPenney advertisements tell consumers to open a credit card and "Save 10 percent today! Plus, save throughout the year with 12 exclusive cardmember offers."

But credit experts warn holiday shoppers to use caution when choosing whether to open a new store credit card.

Two-thirds of consumers who opened a store credit card during the 2006 holiday season were still paying off the debt more than six months later, according to a national survey conducted by LivingWithBadCredit.com, a credit advice Web site.