I second the above post, they are very common and not valuable as some try to make people think. I have 3 or 4 extras and have two more at a buddies house that I can pick up at any time for free.
A realistic price if your trying to sell one is ask $150-$200 but be willing to go down quite a bit, I've seen dozens of them for as low as $25 and even a few left behind at swap meets.