I have two of those type of heaters, and I've never bought one. The first one was abandoned at a job site along with a 55 gallon drum of kero. The architect on the job "contracted" me to dispose of it because he deemed it a fire hazard.
The other one, my neighbor threw out. I grabbed it and put a $12 air pump in it. With a few other tweaks it was making fire and heat reliably.
So for a grand total of almost nothing, I got a 155,000 BTU, and a 75,000 BTU in my heating arsenal. Wonderful things to have. Especially for the price.