Most gas station owners pay between 2 to 10 cents per gallon less than what the price of gasoline is at their pump.
So if the gasoline cost at their gas station is selling for $2.50 per gallon then they likely paid $2.44 to $2.47 per gallon for that gasoline.
Some gas stations may charge a bit more and make maybe 10 to 20 cents per gallon off gasoline but the refineries and gasoline owners are who make the most off gasoline sales.
Gas stations make very little profit off of gasoline sales and make the most profit on sales of merchandise and products inside the stores such as soda, chips, snacks, hot dogs etc.
The gasoline is very little of there profit even though they might sell millions of gallons of gasoline.