E85

If you have E-85 relatively close I guess that's an advantage, though you're somewhat locked into that fuel choice.

Because the energy density of that fuel is so much less than a non-blended fuel you're going to be running through much more of it. So if your looking for a cost savings not sure how much if any you're going to get.

Just have to take your engine combo's needs into consideration along with availability, cost etc...