Chances are he lives near the woods and may have even cut it on his own property.
Often you can pick up wood rounds like that from a blow down for free! It is normally just split up for fire wood and burned. Tons of good wood are burned every year that way, so he isn't wasting it so much. There is a technique where with a special tool you can cut several stacked bowls from one piece of wood, I suppose he could make 2 or 3 but I kind of doubt it just too dangerous when you part it off. It's bad enough doing one. I'll bet he gets 2 or $300 for one maybe more.
If you try this at home take note he kept his speed way down, if it's out of balance even a little, high speed will have it dancing right across the floor or possibly tearing those screws out and away it goes and you hope it doesn't come out your direction, been there done that and have the scar to prove it.
I'd still be turning if I had power and heat to my shop but can't afford the $5000 or so to get it hooked up, maybe I'll do some this summer I still have my little 1000 watt Generator and it will pull my little lathe, I really hate to see it sitting there going to waste. Depends on what the gas prices do this summer it's getting close to $4 here already.

Gabby