It is a commodity...when wholesale goes up all stations go up a similar amount percentage wise (some are cheaper all the time based on additives/detergent or lack thereof). Some “wiggle room” based on when your next truckload arrives, but most stations raise/lower prices based on the announced price of their next load.
http://futures.tradingcharts.com/chart/RB
I used to work in the gas station business and most people dont know or realize selling gas is a far far distant second to where the money is in the business. Far far and away, its cigarette sales and junk food. ie. 5000 gallons of gasoline and the profit is maybe 10 cents a gallon ( or less) . thats 500 dollars, thats peanuts when compared to a dollar or more per pack of smokes and at least a 50% mark- up on junk food. The gas gets them into the station, the extras pay the bills and send the kids to college.