I bought an IWB for a Shield 9 mm at a gun show. They fit the holster to the gun right there and it has been great. I have had it 7 months. It is comfortable, retains the gun, and small.
For me the most important part is the final fit to the gun. I have a Ruger SR9c I may take to the guy at the next show.
I am in Central Florida, but it is a skill I could see being employed at almost any show or even some flea markets.