SS T56

Alright, I'm sure I'm gonna get flamed for asking this but here goes. Is there anything that you can add/cut diesel with that's cheaper? Diesel is once again more $$$ than gas. As far as I know there are no bio-diesel places anywhere around here. I've looked around, read threads and came up with nothing absolute. My truck is an '06 Cummins. Is there a way to use old/new veggy oil, or do you have to buy that $2,xxx+ fuel making kit first? Just wondering, let the flaming begin!

-SS