Check with your local airport for their price per gallon scope
The last 100 LL I bought 4 or 5yrs ago for one my cars that isn't driven on the street yet was around $4.90 a gallon locally work
The E85 I buy for my bracket car is close to $3.25 a gallon, the motor uses around 30% more E85 than gasoline per run so it is close to a wash on the total cost per run other than the E95 is a lot more consistent on the ET at the track up That motor is close to 15 to 1 compression ratio so I wouldn't run straight 100 LL in it, EVER tsk

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)