Larry converted their diesel Mercedes to run on waste vegetable oil. The conversion was easy and the miles per gallon is about the same as diesel fuel at 27 mpg. Vegetable oil is a cheaper and more environmentally friendly alternative to diesel fuel, which costs $4/gallon where they live. Larry gets vegetable oil for free from restaurants. He installed a simple conversion kit himself in 3.5 hours. He has driven over 700 miles on waste vegetable oil, saving over $100 compared to using diesel.