The value depends on if your dad/grandfather shot at Sportsman 58.
If he/they did, it might be worth $100 for the nostalgia.
If they didn't, it's just an obsolete shotgun that, hopefully, still shoots.

 

Actually the 58 is a sought after gun by those who like older shotguns.Remingtons first gas operated shotgun and a soft shooter that points well for most people.$500.00 is a fair price for a nice one.

 

Actually the 58 is a sought after gun by those who like older shotguns.Remingtons first gas operated shotgun and a soft shooter that points well for most people.$500.00 is a fair price for a nice one.

That's key.
To the OP:
If you are just looking for a good shotgun that won't break the bank, a new Beretta A300 Outlander can be had for barely more than that $500. (there's a good used one on GB with a current bid of less than $200)
A minimum bid of $25 on that auction gun should tell you that the gun isn't worth much. Seventy-five bucks should take it.

 

Just curious if it sold and for how much?