The Consumer Reports Holiday Shopping Poll showed up a surprising statistic this year: 33 percent of people in the market for flat-screen TV's were thinking of financing the purchase with a zero-percent financing offer. That's just about the same percentage as last year's poll, and only surprising to us because we've often written about how bad these deals can be. 

Now, they are good deals if you pay off the balance in its entirety before the zero-percent period expires. But, if you don't, there's almost no deal out there worse. The reason: If you don't pay back the loan before the time expires, you're on the hook for all of the interest charges retroactively from the date you bought the TV. And you'll likely be hit with a high interest rate—29.99 percent at Amazon.com; 29.9 percent at Walmart, and as high as 30% at BestBuy.com.

These zero-percent deals may require you to sign up for a store's credit card, which has its own plusses and minuses. You may see zero-percent financing deals for many different time periods: 90 days, or 6, 9, 12, 24 or even 36 months. Many require minimum monthly payments, but some, like Amazon.com's, only charge minimum monthly payments for its 24- and 36-month payment plans.

And as always, watch out for "doorbuster" specials, which are highly discounted (and advertised) TVs you may see in circulars. These are often either a derivative TV (a one-off TV similar to a standard one, but actually a different model with sometimes lower specs and fewer features), or a limited-quantity TV, intended to draw you into the store. But you may end up purchasing something else when you realize the TV you saw advertised sold out hours ago.—Chris Fichera