Cheapest I remember gas is .75 cents a gallon. Im 33. I do remember gas wars in my town where the filling stations would drop their prices to almost nothing to get more business into their stores.
I payed 17.9/gallon once and I'm 51. We used to drive to Canada from Detroit back in the day. Canuck gas used to be 5 quarts to the gallon and their currency was worth less so it was like buying gas at about 1/3 off. Plus we knew a good pizza joint.