I have been using this tip for a while. I have joined the rewards program at the local Shell gas station. For every purchase you make, you earn points toward cents off on 20 gallons of gas.
In order to earn more points, we have started buying our gift cards at the gas station. If we are going to make a purchase off Amazon, we first go buy a gift card, then make the purchase. If we are going to go out to eat, we will try to stop at the station and buy a gift card for the restaurant we are planning to go to. They have a wide selection of other gift cards as well. I save those points up and will be able to purchase gas for cents on the dollar.
Now, if you also go through Rakaten when you are planning a purchase on Amazon, you earn cash back through them as well.
I always love it when I can stack savings upon savings!