Paypal has one of the best promotions of the season. You can get 20% cash back from Paypal when checking out with Paypal at select merchants. The great thing about this promotion is that it can be combined or stacked with other coupons to save even more.
Some of the more popular stores include:
Barnes and Nobles
The Sharper Image
See site for full list
Don't forget to stack them with these online coupons.