Depends on model and condition. Typically $100-$150.
Sears Roebuck co.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf
about $100
I believe that your Sears shotgun is a Winchester model 37A shotgun that was made for Sears Roebuck And Co,.
about $100
You would have to list the model number of your shotgun,to identify the maker of your sears and roebuck shotgun,in order to get the correct buttstock.
No age records, most likely a Mossberg shotgun, values $50-$75.
1949
$450.00
The 12 gauge long tom 1900 shotgun by Sears and Roebuck is valued at $250 in excellent condition. In fair condition, it is valued at $80.
The value of a Sears Roebuck M-66 gauge automatic shotgun depends on its condition. This gun in excellent condition is valued between 120.00 and 180.00 as of 2014.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf