Sunflower oil?

[Kirk]

Over here in Germany one liter Diesel costs about 1.10 Euro when I remember
correctly.
You can get 1 Liter sunflower oil from the supermarket for around
0.75 cents per Liter, so it is cheaper to fill up your tank from the supermarket.

http://journeytoforever.org/biodiesel_svo.html

check out elsbett.com

[GM]

A friend of me let his Car modify by this german company. http://www.biocar.de/ 
He is satisfied with his "new" car for years now.

You start with normal diesel, then switch to bio oil (sunflower oil, oil from french fries or s.e.)
and shortly before you will park the car you switch back to diesel. So the gasoline tube will
allways be filled with diesel when the car is not in use. The second tank and the tubes for the
alternative oil will be heated in winter. It is a very comfortable system.

Bye Markus