The Mike Horn is listed on amazon.it for € 128,27
I would deduct around 30% because of the missing box and sheath.
So I would say € 90.
I found few italian websites with old entires on the PocketGrip 799.
The price was around € 70.
Since the sheaths can still be found, I would only deduct 15%.
So I would say € 60.
This is just my personal opinion.
As a collector, for example, I would look for a complete set. As a user, it would be ok, also without sheath.