Following on my previous post (HERE), Shawn at Miles to Memories (or in this case, Frequent Miler - who he also writes for) pointed out that the previous Staples deal can be similarly used for some great deals at Chevron/Texaco, Hyatt, Cabelas, and Sears. Read Shawn's run-down HERE. But also see my previous post for some ways to think about and take advantage of this deal.
UPDATE (5/29): Unfortunately, Ebates is no longer paying 4% back on gift card purchases from eBay. It is down to 1% for all eBay purchases via Ebates (the percentages change all the time - and you should use www.cashbackmonitor.com to always search for the best payback). Even with the decrease from 4% to 1%, buying these gift cards can still be a great deal. But also know that you can always buy gift cards at a discount. GiftCardGranny is a website that lets you check multiple websites for the best discount on gift cards from any particular merchant (just be aware that some are eGift cards, where you get faster delivery but no physical card, whereas others are physical gift cards that you'll have to wait for via shipment).