Gas prices are determined well before they reach the pumps. As an individual consumer, you have very little to do with gasoline prices in a commodity market which is based on overall consumption / supply and what Bernanke ate for breakfast. Most of the profit for EXXON etc is at the commodity level, if they can't sell it to you directly, they'll sell it to another station who will sell it to you instead.

I know this post is old, but I saw it in the "recommended thread" section and couldn't resist!