Good point. When I was real broke a few years ago, I owuld go to the Gas station and fill my Express tank full with just what was left in the hoses. Because they go down, and come back up, you can usually get a good 8-10 oz out of a hose. Three hoses per pump, six- 12 pumps. Full tank.
This diddnt work at all stations. some must have some sort of drain, or valve... but it worked in 8 out of 10.