Most gas stations are owned by smaller groups, or even by individuals. Very few are owned/operated by the large oil companies themsleves.

While there has been consolidation, with some groups owning many gas stations (e.g., Circle K, 7-11, and even Maverik) there are still many smaller groups out there. You can have one individual or small group with a Chevron Station, and then 5 miles down the freeway, another Chevron could be owned by another individual or small group. One way that you can often tell is to look at the name on the convenience store associated with the gas stations. If it is a Jim's, or BIG's, or XYZ's then it is a smaller operator. You do see many Circle K's and 7-11's that still have a major oil brand on the fuel canopy and pumps.

I've also seen where a small group that only has 3-5 stores gets a much higher price from the supplier (in this case Chevron) than a larger group that has 30-50 sites branded with Chevron... and the really large groups like Circle K (whether for a Chevron branded site or a Circle K Branded site) will likely have the best price because of the larger volume discount that they demand.

So pricing strategies can be vastly different from one site to the next... especially when they are owned by different groups (even though they have the same brand).