I posted here before about my space heater and cobbled together pressure burner I used in the past. This a syphon burner running on waste vegetable oil, but these things can burn ATF, motor oil, just about anything. The kit I used is $600. You can complete a conversion for about $700 or spend over $1,000 depending on how many parts you can salvage. You need a constant level tank and an air compressor for a syphon conversion, but it's been running great. It hasn't needed a cleaning so far this year. I was cleaning the pressure burner once a week, twice when it was very cold. It seems like a lot to spend, but it pay's for itself fast when the fuel is free. There are a couple threads where everyone is concerned about the cost of fuel. I can get heat, light, electricity and run all of my vehicles on waste oil. The savings can go back into preps. This "hobby" has really been a life saver (at least a house saver) since I was injured in a crash. We have been getting by, but it would much worse if we were paying for all the fuel.