Chevron is a deal at autoparts stores with rebates or buy-one-get-one. At Walmart or target, the Regane all-in-one treats 35gal and is usually the $/oz winner. Can easily take care of 2-3 tanks, or run it for a tank then add 2oz/tank (similar to Redline dosing) for a few.
Lots of ways to skin a cat.
I will guestimate that regane all-in-one or high-mileage could boost MPG every so slightly more vs techron (due to friction modifiers). We're talking 5% or less, though, if actually measureable.