50-350 usd
100-400 USD depending on condition.
First of all you have the "sportsman 48", "sportsman 58" and the "sportsman". If it is a plain sportsman it's value depending on it's condition is from 150 to 200 dollars.
It is a St. Louis Browning made by Remington for Browning. It was made around 1940. It's value is probably around $250.00 without seeing it. The B means it is a 12 gage. A was 16 gage and C is 20 gage.
Value of 75 Cherokee 12 gage single shot
Not marked, Model 9
Check this page on the Remington Society of America for a list of places: http://remingtonsociety.com/rsa/service
25-100 USD
50-100 USD
Impossible to value with just the serial number.
Sounds like a model 11, 1905-1947.
No such model name in the Browning line.
I got one used but like new for 250!