Newby questions are never something to be sorry for - it's how we all learned!
The normal price is about $100 give or take.
Barney Hartman was a C.I.L. pro shooter back in the day- not sure if he is still kicking or not, lost track of him a while back, he was one of the World's finest skeet shooters- anyway, I digress!
Mr. Hartman modified the chokes on his early model 58 and 1100 guns by honing them out with a brake cylinder hone and patterning them , then honing them.
I've seen it done with emery cloth on a dowel as well, but it takes several grades.
These days reamers are mostly used.
Personally I would just use the non tox stuff available or hand load it, in faxt that is what I do .
Cat