How much does Bio-diesel and Veggie Oil cost and where do you get it from?

Bio depends on where you purchase it. We filled up in Portland at $3 a gallon, in Santa Cruz at $3.15 and if you find a home brew you might get it cheaper still. If you make it yourself after the set-up cost it'll run you about 70 cents a gallon.
Veggie Oil is free. The filter system that is part of the conversion allows you to drive on used grease so you are actually using a waste product for fuel. If you are settled in one place, you just find a nice restaurant that has clean grease and ask them for it. You can set it up so that you have a regularly scheduled pick-up. Usually the restaurant has to pay to dispose of their used grease, so usually they're happy to give it to you. If you're traveling it's a bit more tricky, see below.