I started making my own biodiesel (BD) in 2008 ,last September to be precise,the initial set up cost me slightly over £ 1,000.00 ,so far ,not only have i made all my money back from what i've saved on not paying pump prices, i'm now about £ 150.00 in the black ,i'm lucky in that i don't pay for waste oil ,so my only cost is the chemicals to make the BD and the cost of electrcity to run the processor,it currently costs me about 23p a litre to make ,i nomally make about 90-130 litres each time ,i can honestly say i've not brought any "white" diesel in over a year,if i make BD from liquid oil it stays liquid down to MINUS 3.5 deg c ,if i make BD out of solid veg oil it stays liquid to 3 deg c ABOVE freezing once below these tempretures the BD starts to thicken but once the temp rises the BD liquifys again,i've run for the last year purely on B 100 (thats 100 % BD) with no engine modifications at all,BD cleans all the insides of the fuel system so after the first 1,000/1500 miles i changed the fuel filter,my engine runs quieter now as BD is more oily than white diesel,my emissions are really low, the only co2 that comes out my exhaust is what the plants absorbed when they initally grew.if anybody wants any help or more info,feel free to get in touch,oh i nearly forgot you can legally make 2500 litres per year before you have to pay tax on it.