When I was in Oklahoma this past week, I found that there was about a $0.30 difference between "pure gasoline" and "ethanol laced" gasoline.
My son and DIW in Oklahoma have two hybrid cars. They went back to the "non-pure" gasoline after a year of checking mileage using "pure" vs. "non-pure" gasoline. They found that the mileage difference was so minimal that they now just fill up their tanks wherever it is most convenient.
I just fill up when needed. My truck is one thing. But, my little Ford Fiesta is another. I get about 37 MPG motoring around here, and about 44 MPH on highway trips.
Ken
