$100... some shotguns the barrel is crap. i would say there is about a 10% chance that the threading will be messed up. I saw a 1100 get bored for a choke and there was no threads on the bottom part of the barrel and really deep threads on the top part. I have not seen this happen on new model shotguns, seems like shotguns from mid 80's back
IIRC my father had a Rem 1100 rethreaded about 10 yrs back. He stuck the barrel in the ground while crossing a fence and then fired it. Had it cut and rethreaded for Rem Chokes. It worked well after ... can't remember how much it was to have it done, but it was not expensive IIRC - a lot cheaper than a new barrel. Someone from down McComb way did the work.
I have Rem-Choke reamers and correct tap. (32tpi) (Manson Tooling). Just finished two Home Defense bbls for Carlson Breacher Chokes last week. 'Am slowly trying to retire from gunsmithing. I can do the work here at shop, or you can purchase reamer, tap, lathe etc, if you wanted to get into it. Manson reamers cut a step for a skirt on the choke tube preventing blow out, or stuck choke tube.
Also have long forcing cone reamer that will improve pattern and reduce recoil, if your interested.