Its one of those games that when a dealer brings one in they try to get top top dollar for due to not many being around. It wasnt a big hit on site which is why there are not many.. nice novelty but it quickly wears thin due to hardly any depth to a game.
Pay what you want for one.. you can pretty much dictate its price within reason but a seller will want plenty and to be quite frank a buyer would be looking to bargain on these.
Personally, id price it working at around $1500 tops... almost all are projects though and so price is what your times worth.. $600 - $800 is what id be offering on the outside with a damn good attempt at $400