It can make gas cheaper *IF* it is used for that purpose. It doesn't cost as much to ferment a little corn or grain and distill it as it does to pump oil out of the ground and crack it.
On the other hand, *IF* it is added to gas to reduce polution, it mysteriously costs a lot more.
Used in carburetted engines, there is a very slight decrease in performance because alcohol doesn't burn quite as hot as petrol. But, not enough to really notice unless you are racing.
In fuel injected vehicles designed for real petrol you have a problem. It seems the added oxygen fools the injection system into believing the mixture is too lean. I had a '91 Jeep that dropped some 18% in fuel economy when the idiot politicians mandated oxygenated fuels. This was a greater increase in fuel consumption than the claimed reduction in polution, so this "clean burning" formula was increasing polution.
