I don't know what state u r in, but it seems that your state does NOT have the protections mentioned in this article...If I can stand between 2 gas stations half a block apart, and pay $3.49 at one and $3.34 at the other, someones gouging something. Gas station #1 is a Speedway with a full store and deli attached. Gas station #2 is a Mobil, which may or may not contain a coffee machine, and a soda fountain.
MY guess would be that Speedway is tacking extra nickels on to the price of their gas if they're not happy with their food sales for the day.
it seems that Mobile sevice stations which are oil company owned, are low balling to put speedway, out of business? at least this is a possibility of what is going on in your neck of the woods? but i really don't know...it is interesting and strikes interest to see such disparity in retail price...
this is a great link, tons of info on ''how it all works''
http://auto.howstuffworks.com/gas-price.htm
care
Station markup - While it isn't represented in the diagram above, of course some of the actual money you spend at the pump does go to the service station. Service stations add on a few cents per gallon. There's no set standard for how much gas stations add on to the price. Some may add just a couple of cents, while others may add as much as a dime or more. However, some states have markup laws prohibiting stations from charging less than a certain percentage over invoice from the wholesaler. These laws are designed to protect small, individually-owned gas stations from being driven out of business by large chains who can afford to slash prices at select locations.