I'm not sure of the decimal purpose either but I know a little about who sets the prices. Most brand name gas stations are franchises, and they can be owned in one of two ways. You can buy it outright and make your own prices, but being under the franchise's name you still have a limit that you can't go beyond. These stations are usually the most expensive. The other way which is more popular, is to own or rent the physical property that the station sits on, and 'rent' the name. Most people buy the property. In this case the prices are set by the big company, such as Getty or Mobil, and they dictate the exact price that you have to charge per gallon and you only make about 4¢-5¢ a gallon profit this way. However, you can sell anything else you want out of the station such as soda/snacks/maps etc, and set your own prices on them provided you have the liscence to sell these items. Also, in the second option, if you have the facilities for automotive repairs, you will own that part of the business outright. It's a seperate corporation and you can charge anything you want for labor and/or repairs. No one can dictate auto repair prices/profit even though it's under the franchise name. All profits are seperate from the gas station part of the business and the brand name can be used on your mechanics uniforms if you wish. Using the second option, the big company is also responsible for any mandated upgrades to the pumps/tanks and anything else pertaining to the gasoline end of the business. At around 5¢ a gallon profit you don't make much, but the prices are usually much lower than your competitors. In the end you sell a lot more fuel which brings in customers to your auto repair shop, and that's where you make your real money.