There is no S&W Model 4T942
There is no S&W Model 150
50-400 USD or so
100-1000 USD depending on specifics
Depends on the make, model, and condition. A used S&W Model 10, with a 4 inch barrel, in good condition may sell for $200, more or less. An H&R .38 S&W might be worth $100, and a scarce Colt in new condition may be worth $2000.
10-400 USD depending on specifics
Your smith and wesson model 10 with a great nickel finish remaining will be worth between 375-475 dollars.
The gun is likely a Harrington & Richardson (H&R) model 925. The caliber is .38 Smith and Wesson (S&W) special, not to be confused with .38 special (SPL). You must shoot the .38 S&W ammo, not .38 spl.
Which one? There are dozens of models of S&W Revolvers from that period. It will depend on which model, and what condition. I just bought a New-In-Box K-38 Target Masterpiece that is worth around $900. A heavily worn Model 10 might be worth $100.
100-500 USD or so
J frame, usually in 38 special
S&W never made a 38 Magnum. A Model 36-10, AKA The 38 Chief's Special, which is chambered in 38 Special, is worth 100-400 USD
No such model