This is a “Poor Man’s Story Lock”, Slaymaker a lot of different locks of this type around the 1920’s and 1930’s. If it is in good shape (no major dents, not frozen up, no drilled rivet heads, etc.), it may be worth between $20.00-$50.00 to the right buyer. Having a working key always adds to its value. Hope this helps.
Cheers, Mike DC/