If the pipe is still made you have a pretty good price point to start with. If not what you can do is just look around; people bought and sold those pipes before, just look at the prices, pipe condition, age etc and compare to the pipe you wanna buy. Google is your friend.
A decent pre-republic is worth anywhere from $70 to 150, even 200. Some Peterson pipes are listed here with their prices http://pipedia.org/index.php?title=Peterson
I remember some pipes having estate prices here, especially on odd pipes http://www.pipephil.eu/