Impossible to answer without more details. What is the intended use? What is your skill level? How much money do you have to spend? How old are you? Where do you live?
Best left to a gunsmith.
Best course of action is to take it to a gunsmith.
Best left to a trained gunsmith
22-72
Smith and Wesson Model 1
S&w
All of them have a sn.
No published sn data that I am aware of. Best guess is 60-68
A .22 caliber Iver-Johnson Cadet revolver.
300-500
Impossible to answer without knowing who made it.
l Blue Book of Gun values