You could consider distilling your own ethanol and running 95-100 precent E? I'm planning on building a still for this exact purpose and buying corn feedstock to make E95 (or 100 if I use a molecular sieve to filter the extra water in the blend) for about 50cents to a dollar a gallon. If you live close enough to a saw mill you can take the saw dust off em and make ethanol from wood as well by using a relativley simple process described here:
http://www.green-trust.org/sawdust_ethanol.htm
In this case if you could get free sawdust from the mill you could drive your car for maybe 10 or 20 cents a galllon after that initial startup investment in building your fermenting containers/still and buying the enzymes(which if done smart could be quite cheap by raiding your local junkyard or garbage lot).
This is also legal in the states (not sure about most other countries) if you apply for a free permit from the Bureau of Alcohol, Tobacco & Firearms, but if you go the legal route in the states you will have to distill outside, have the possibility of them coming by and inspecting your operation, and also using some kind of additive to keep the alcohol from being "beverage grade"; usually by just adding some regular fuel(the ethanol must be water free to do this or the gasoline can seperate from the rest) or a small amount of methanol (no concern with some water in the mix).
Also it should be noted that going the legal route can make you elligable for some tax rebates for driving an ethanol car or even for selling ethanol fuel.
Plus I want an Evo that runs on sawdust, don't you!