PDG Paramounts are relatively commom and regularly show up in very good or better condition. PDG's with 600 Ultegra and Dura Ace are less common.

$500...maximum if its a Waterford frame
$200...minimum if its a Panasonic frame

Its worth is all relative to the overall condition. Is there any rust on the component hardware? Is the headset ($50) brinneled? How are the tires ($40)? It appears to be a 54cm +/- which happens to be one of the most popular sizes. Does it fit you? The bike as picture is at least 2 sizes too small for the current owner. Is it a Waterford or Panasonic frame?

I'm fairly certain its a Waterford bike based on the rear derailleur cable stop design.