Other added cost include converting fuel lines from rubber to metal and extra filters to the engine.
The cost to manufacture is about $1-1.50/gallon IN THE US. You also need to check the grease used on the island. If it has animal fat then do not use. The pure vegetable oil is better and even that varies.
If Eddie has the equipment to seperate the glycirin from the oil then it is worth the effort. Since you do have to mix Methanol according to the amount of oil you have, there is a test and some math to figure it out, you have to have certain safety standards. Again this is in the US. Methanol is volitale and should not be in residential areas when you have large quantities.
I do not represent this company but they have a "refinery" that will produce 600gal/day. http://www.extremebiodiesel.com/
As C2C stated the ROI is questionable but I think it is worth looking into.