Garage Heat?

I would love a waste oil heater, but I'm not in a permanent living place at my garage.

Eventually, I'd like to have a gas radiant heater and a waste oil with good insulation. I don't do enough oil changing on my own to heat an entire shop all winter, but I can get enough waste oil from people I know to probably knock 3 months off.

I think I'll start with Hammer's suggestion and go with a radiant gas for now, until I get a better garage over me.