It depends on the year, manufacturer, and condition, but if it's a genuine antique and in good condition, you should be able to get at least $1,500 for it.
Parker 12 ga muzzleloader
sawed-off double barreled 12 gauge Remington shotgun.
Gun shop, gun show, Shotgun News, Gun List
The double barreled red chieftain of course!
50-100 or so
Stephens
'Granny' used a double-barreled , 12-gauge shotgun .
No.
Stevens Arms made the Ranger shotgun for Sears & Roebuck. Production ended about 1930.
Probably early 1900's
Just another model in the Stevens line.
Unlikely more than 125 or so