First you must determine who actually manufactured the firearm and its appropriate model number since Sears contracted with several different companies over the years and few gun value sources will list Sears marked guns. Winchester and Hi Standard were the two main suppliers although they weren't the only ones. Once you know what it is, a recent copy of the book Modern Gun Values can provide a good estimate (read the sections about rating the gun's condition and examine the gun dispassionately) or take it to a local gun smith and pay him to do the research and provide an estimate of the value.
I will offer that a gun sold by Sears carries a lower value than the same model with the actual manufacturer markings and without the Sears markings. Sears generally paid low ball prices for bulk purchases and sold the cheapest models so a Sears marked Winchester 30-30 (for example) will generally be less attactive than a Winchester Model 94.
If you are trying to place an insurance value of your grand dad's old gun, I can almost 100% assure you that it has more sentimental value than collector value and the collector value won't exceed about $150.
What is the value of a Sears Roebuck 22SL OR LR MOD #27327010
Wat is the value of 22 caliber sears and roebuck model 340530430 lever action rifle
This model was made by Daisy. Its a model 1894 and shoots standard .177 caliber BBs'
where can i get a magazine for a sears and roebuck j.c. higgins model 46 dl-10319840 22 cal. lever action rifle
No publicly available information
1958 to 1961
Sears Roebuck model 108.1501 appears to be a type of hacksaw according to the online Sears listings. There was no information regarding when this hacksaw made its debut.
what year was sears roebuck model 61009 17 ft aluminum canoe manufactured
it might also be a marlin, but try any local gun show