Semi Gloss vs Satin

I was driving through town the other day and passed a Sam's Club on the east side of town. I saw a gasoline tanker truck leaving the fuel pumps there and get on the highway behind me. When I arrived on the west side of town I went to the Sam's Club there, which is about fifteen miles west of the one I passed earlier, and after shopping there saw the same gasoline tanker truck at the fuel pumps. Now, riddle me this Batman. The gasoline price at the Sam's Club on the east side is $1.84 a gallon and here at the Sam's Club on the west side the price is $1.94 a gallon. The fuel came out of the same truck so why is there a price difference? Explain that to me, Mr. Smarty Pants.