It may not have one. Rifles and shotguns made prior to 1968 were not required to have serial numbers.
Try e-gunparts.com
$100 for a pretty beat up one
It was made by Stevens, the model is: Stevens model 940
Serial numbers were not required prior to 1968.
50-250 or so
This was sold by Sears , made by Stevens between 1912 and 1942. It was not made by Browning.
I can say that Stevens began production of the model 94 single shot shotguns in the year 1929.and finished in the year 1945.
Post the serial number of the gun and I'll let you know.
not sure check sears
$50-$100, depending on condition.
50-500 usd
No published sn data