The old adage "If it sounds too good to be true, it most likely is" holds true here.
Yes, it would be great to get a pristing Kindle DX Graphite 3G international version for USD 159. Does it sound very likely? Not really.
There must be a reason why there are also ebay auctions where those Kindles are sold for 250$ and the buyer writes a happy review - mainly auctions where you see original pictures of the device in question (and not just a "sample image") and the seller is an ebay member with 100% positive feedback and a solid number of sales in the past. (I also bought - and sold - Kindle Keyboards over eBay).