I have a LARGE van that I don't drive much anymore. The tank is quite low. If I had filled it a couple months ago, I could have saved ...maybe $10 over what it would cost me today. But, on the other hand, gas/petrol degrades if it just sits in the tank, and running on very old fuel can cause problems....so I will buy just enough for current needs.......and I may just try to sell the van! If I got $4000 for it, that would buy a LOT of gas for our 2 smaller vehicles.