Mike, the case rims will be something to deal with.
Look closely there.
At some time there were shotgun cases with solid plastic case heads.
I've heard of guys using them with the rims turned/ground/trimmed off. Haven't seen these cases around anywhere though.
A lathe might not be necessary, you might get away with getting crafty with a drill or something like that and some sandpaper or a file.
Still - at the end of the day, that thirty bucks might seem like a bargain once you have to deal with all the other hurdles.
Buy once, cry once but you get to shoot your gun.
Also, if you are considering having someone make adapters for the 209 primer pocket - they will cost money too.