There is a simple and somewhat cost effective way to heat oil. I know it may sound funny, but goto your favorite store, and this time of year almost everywhere has them, including the supermarket. Get yourself a large turkey fryer. Dont overload the pot, just like you are cooking and that will give you a small batch and heat reletivly quickly. I know some people goto a water heater in a larger system, but a turkey frier is a good start. I think Trav used that trick for a while........
Disclaimer - If you use the pot for motor oil, do not later use it to cook your Turkey...... Make this a deticated unit. Just putting this out there, I dont want the stories in a couple of weeks "I fried my turkey for thanksgiving and it tasted really funny.... I only had one so I used the one that I had been heating my waste oil in......"