If you make a purchase with gift cards, you will most likely not receive cash back on that purchase, but you should check the terms and conditions before trying. When it comes to coupon codes, it will depend on the retailer. I have used coupon codes in addition to the cash back through Ebates in multiple cases and they have always worked out for me, but there are some cases where this won't work. Be sure to check out the store exceptions page on Ebates for specific details for each affiliated retailer.