You can buy a $100 Shell Gift Card at Shell for $90 on Groupon.
Limit 1/person. Must provide full name & shipping address upon purchase to facilitate redemption. Valid only at participating locations. Not redeemable for cash unless required by law. US residents only; does not ship to US territories, Hawaii, Alaska and Canada. Allow 7-14 business days for delivery. Valid only with voucher email offer. Not valid with promotional codes, gift codes, or Bucks. Do not present voucher directly at Shell locations; must present Shell gift card, which will arrive via mail.