Bing is doing away with Cashback so if your looking to buy something, best to do it now. Ebay is 8%, but there are a ton of other stores. Ends July 30 at 9pm EST.
http://www.bing.com/shopping/pages/stores.aspx?scope=cashback&FORM=CBFS07
http://www.bing.com/shopping/pages/stores.aspx?scope=cashback&FORM=CBFS07