Check out smith-wessonforums.com They have experts that can help with all things smith.
100-425 USD
Need to know caliber, barrel length, and type of action.
It should be marked on the barrel.
357 Magnum
Try e-gunparts.com
300-700 USD
The Model 57/657
Smith and Wesson Model 1
No
I believe that the last Smith and Wesson hammer less model was the stainless model 60 chief,s special that was made in 1998. IT had a 2 1/2in barrel and was double action only.
Impossible to answer without knowing the caliber.
22 long rifle