Staples has great deals every week. They usually sell out fast the first day of the ad though (Sunday usually). My Staples however restocks the shelves midweek usually and I get the deals then without the crowds.
The Back to School card really isnt worth it unless you are going to buy alot of supplies. There is just too many things they dont allow to be qualified as school supplies. However, if you are buying large quanities it works out.
Also there have been alot of printable coupons that have been really good deals. You really have to jump on those though as they are out of prints fast.
My favorite one this year was the 1.00 off 3 Roseart products and the crayons at
Walmart were .25 so they were free. Also remember you can print those coupons twice. Some people say they have problems with printed coupon sites but if you are on a reputable site you are usually fine. Check manufacturer webpages, and Facebook pages.