Or maybe the station owner will demand sexual favors and your first-born child, or that you join ISIS, or that you get out of your car and do a strip-tease beside the road.
This would last about as long as it took the first customer to notice that the previous customer paid $0.01/gallon less than him, whereupon the gas station owner would get a (well-deserved) online lynching.
Not to mention that virtually every gas station I've seen in my life has the price prominently posted on a large display. You think customers wouldn't notice if that were constantly changing?
We won't even go into the over-the-top "charging $5.00/gallon more" scenario. Any station that tried that would be out of business within days.