I drive about 3-4 miles from my home to gas up at a convenience store with ethanol-free gas. So says their pump, and when during Hurricane Isaac I had to use ethanol-laced Chevron gas, my mileage dropped noticeably. My station charges about .10-.12 more than the Walmart two miles closer to me. However, I get approximately 10% better mileage on the pure gas than with ethanol, for a 4-5% increase in cost; so I think I'm doing okay. Since the store is a bother to get to during weeknight rush hours, I fill up early on Saturday or Sunday morning, which can last me two weeks (18-gallon tank).
If the store goes ethanol only, then I'll pick the cheapest, usually Mall-Wart.
If the store goes ethanol only, then I'll pick the cheapest, usually Mall-Wart.