Thanks, everyone. Putting the "4" in front of my gift card is not working for me, at least it didn't work last night. I'm going to try again tonight and call if I have to.
I bought the gift cards from one of my local supermarkets. In Ohio, we have a chain of supermarkets that sell gift cards and for every $50 in gift cards you buy, you get 10 cents off per gallon of fuel. A few times a year, you get 20 cents off a gallon for every $50 in gift cards you buy. Lots of people get free gas.
I'll let you guys know if/when this works for me. For some reason, I select visa, put the extra "4" in front of the gift card number and use the renewal date (12/2012 for my gift cards) but instead of the charge going through, I get a "declined" message. Frustrating but I'm starting to worry that I bought all of these gift cards and I can't use them for my maintenance fees.