I have seen them range between $300-$1200 depending upon condition.  Pictures would help us tremendously in narrowing the value range.  Basically, if the stock is cracked/broken and the metal finish is gone or re-blued it is at the low end of the scale.  If the shotgun is in 90%+ original finish with no modifications it is at the top end of the scale.  Everything else is in between.

They are scarce but don’t seem to have a good price to rarity ratio.  There is not a huge collector market for them as they are more a novelty as a garden gun than anything.  I see quite a few for sale but not many selling at the higher asking prices.

Regards,