Originally Posted by Lumpy
Gonzo has a few Montana cards, (including a rookie). The last time he checked Beckett, they were only worth around $20-$30.
Edit: You can check out their value here... http://www.beckett.com/search/#term=joe montana
(Of course, it looks like you have to register.)
It depends, if graded by a legit company, a high grade card can bring some serious coin. If its raw and kinda tough looking, $20 may be generous. Lots of cards out there, so condition is the be all make it or break it for newer material.