The seller is pretty clear in his valuation - a new dubl duck like the one supposed to be in the box is worth $200, however a sealed box on its own is worth between $395 and $695 plus shipping, regardless of the content.

Clearly not many people see it the same way because his auction ended without bids. He has relisted it, though, waiting for somebody willing to buy it. I don't think his chances are particularly good.