Kroger (Ralphs here in LA) has some excellent gift card deals on a regular basis. With the discount alone, many are worth buying. But with the 4X fuel points, it makes it terrific...a $250 purchase can reduce your fill up by $1.00/gallon...or easily $15-20. Yes, Costco is cheaper, but the lines are a mess and they're usually out of the way. Shell stations are a dime a dozen, and if you can find a Ralph's station, they're almost as cheap as Costco.
In any case, here is a REI Gift Card with a 10% bonus...again, REI isn't the cheapest, but for people who shop there this is a nice little savings. Looks like you can buy up to 5 cards, or a $50 bonus on $500.