http://www.bing.com/cashback/
for bing
online retailers include: sears, best buy, walmart, newegg, tiger direct, and LOTS more. anywhere from 1-40% BCB. They have a live list of retailers on their page. The % CB varies and they'll have special promotions that will not be listed on their main site. Sometimes you will have to actually search the particular store and it will show up as a higher % CB. Normally sears is 8%, but it has been up to 20%. Best buy is at 5% but right now it's at 10%. So basically you pretty much don't have to pay tax.