This is often done so that they can easily compete with each other. Say one gas station is charging $4.10 for gas, but the one across the street is selling it for only $4.07. This gives the cheaper gas station easy business. When people see that the cheaper gas station is full because they have more business, they’ll be forced to go to the more expensive gas station if they want to fill up any time soon. Then there’s the gas station that’s charging only $4.01, but they only take cash. This is either easy business for them or easy business for the other gas stations, depending on whether the customer has enough cash or not.