It's all good information flip flop.
I used to make side money hauling away old tubs (mostly free ones) and refurbishing for sale. Along with service. Got a 7 yo D1 Diplomat once for free because the guy said it leaked and he bought a different tub, I didn't argue. Put about 400 bucks in parts and the same in labor and sold it for 2500. It was full and hot and used by me in my garage when I sold it. I have 100's more examples just like this. If done right it can be lucrative with plenty of buyers and sellers/givers awayers. But alas I couldn't make a living out of it so had to have a real job also (fleet/equipment manager (166 trucks and vans) for a mechanical contractor 25 years). I am about to stop maintaining my actual plumbing license, I never use it and won't ever again. I thought I wanted to be a plumber but really didn't plumb for more than 5-8 years before being offered a different job in a different field. Maybe I was a lousy plumber? Or I hated dealing with poop?
I also cut plenty of tubs up with chainsaw/sawzall and hauled them to the dump! Generally around 40-50 bucks to dispose of a truck full of fiberglass, foam and wood/plastic/stuff. 20-30 bucks for fuel. Steel motors/pumps and heater tubes brought 10-15 cents per pound. If you clean the copper from the motors you can get a lot more but, that's a lot of work. I charge 200-400 for a disposal.
The days of 2 jobs are over at almost 60.