Actually, the model for most stations is to sell gas at tiny margins and make their profits on that overpriced "food, drinks and junk". I'd venture to say retail gas margins are as low as they've ever been.
Ok.... then how to explain rising prices without new shipments of gasoline.... The cost of the gas in the tanks don't go up while sitting in the tanks, yet the price charged DOES go up....
And even if this is in anticipation of the next shipment's cost, I have a problem.