said by clone:Lots of places around here do this. In great big numbers on the sign is how much the gas costs per gallon* when you buy a car wash. In smaller numbers down below somewhere is the real price, usually 20-30 cents higher because the car wash costs $10.
If you had a large motorhome, you could get the car wash, not really use it, and save a lot of money buying a couple hundred gallons at those prices.