My best guess would be in the $200 - $250 range but that is based on ebay prices for a mint in box with papers knife...
I just did a quick search and here is an example:
http://cgi.ebay.com/BUCK-KNIFE-M9-BA...QQcmdZViewItem
Prices on ebay are impossible to predict however... the same knife with lousy pics and a poor description might sell for $150 or some nut case may come in and pay you $550 for it...
