Each brand is priced differently, and each station buys a different brand.
The profit margin is very small for gas stations. Selling gasoline does not keep a station in business. The profits come instead from automotive repairs and food, drink and cigarette sales.
As the price continues to rise, remember gas is still a bargain compared to what it cost in the early '80s. It is also a bargain compared to other liquids.
"Compared to a gallon of milk, bottled water, soft drinks, beer, things like that, gas is still cheaper than those commodities," says Gary Harris of the North Carolina Petroleum Marketers Association.
The price is also a bargain compared to what gas costs in other countries; it is $3.50 a gallon in Japan and $4.50 a gallon in Great Britain and Norway.