My community college welding teacher raved about gasoline-oxygen cutting torches. Compact, cheaper to use, powerful. He said you won't see them on the shelf at the welding supply stores because those stores are owned by companies whose main gig is bottled gasses.
Never did use one. I see they can be found easily enough online. They's a whole lotta steel cutting goin' on here:
https://www.youtube.com/watch?v=SabpLuqd2ZA