Where do QuikTrip and Racetrak get the gasoline they sell?

Refineries sell the fuel they produce to bulk suppliers of fuel. Oil from gas stations of companies that do not own refineries is bought from these bulk suppliers. Even oil sold at branded gas stations may come from bulk suppliers of fuel. The difference in brands of gasoline are often only in the additive package, which is a small amount of fuel additives. Each of the major oil companies has its own formulation of the additive package, although it is important to note that the EPA mandates a minimum level of fuel additives. Generic brand gasoline simply uses a generic additive package which meets the EPA's minimum requirements.