Before buying anything online, I check two places:
- The Chase Rewards Plus site, to see if I can get a cash-back bonus for buying through this site. I know Citi has a similar shopping portal, and other credit cards probably do as well. Cash-back bonuses can be an additional 1% to 7%.
- RetailMeNot, to see if there are any coupon codes I can use. This site has official (direct from the web store) and user-submitted coupon codes.