I've always recommend the appleseed for best cheap route. But you have to build it. You might be able to find someone local that can build one for you, craigslist. If you have the cash, go with a biopro. There's a demo on utah biodiesel supply. Look at it.
Edit: I love my appleseed. Best use of a water heat ever. 2 years and still going strong. Don't have to worry about insulation during cold months except the piping. Good luck.
Eugene