I have a Flipper Pool and it's a great add-a-ball game. Make sure it has all the plastic drop-down pool balls 1-15 in the backglass animation unit behind the top portion of the backglass.
Here's a few prices:
Go to bostonpinball.biz then click on ebay sales summary - scroll down to your game to see any sold on ebay during the past 4 years or so.
Mr. Pinball 2011 price guide - $825 - very good condition and working.
Eric 8th edition price guide - Class 1 - $1050
Class 2 - $700
Class 3 - $375
You can't go wrong buying any decent Gottlieb wedgehead so don't pass it up!
Dave