Add five $20 gas gift cards to your cart for $100 at OffceDepot.com, and apply code 81356016 to drop your total to $80. With free shipping, that's the best deal we've ever seen of this kind. Even though it says that there is a limit of one per customer, you can in fact buy 10. You'll get a promotinal code in the mail after 1-2 weeks, which you must redeem online within two months to get a gift card in the mail. The card can be redeemed at ARCO, ExxonMobil, Marathon, Shell, Speedway, or Sunoco stations. Of note, since Office Depot charges sales tax on these cards (in States with Office Depot locations), and you'll be paying your state's gas taxes at the pump, you end up being taxed twice. Even with taxes, it's the best deal we've seen on gas.