I was driving by the Sunoco in downtown Shippensburg when I saw a sign that said: Every Sunday from 7AM to 7AM (over to Monday they mean), Sunoco will give you 4 cents off of every gallon, every grade.
Well, I like the idea of that. I don't know whether this is a nation-wide gig or just a local thing, but I suggest you zoom off to your nearest Sunoco and find out.
Four cents off a gallon. Yeah. I'll take some of that gasolina.
(But for those of you that can't cash in on what I will affectionately term "gas sundays,": here's a handy link to the USA Gas Temperature Map that will compare prices between all of the stations in your area.)