Need a detailed description of all markings and features and the serial number.
It is a Smith & Wesson, possibly a model 17 K-22 Masterpiece. They were made from 1947-1993 (in the blued version shown in your photo) and are extremely good target guns.
Impossible to answer without knowing who made it.
Samuel Colt invented the first revolver. I'm not sure if it was a six shot but he invented the first revolver.
No more than 50 USD. For that, it would need to be NIB with all paperwork and a perfect box.