Hi Rich,
This one is easy to figure out <g>. Saito's auction is one bid and one bid only! Ebay is not. Hence a colllector who bids in Saito's auction only gets the one shot (bid) at the chip. People will have a tendency to bid a little higher in a one bid auction.

Secondly, many of the people on Ebay have no idea how significant the Primadonna 50 cent chip is. They have no idea of the history or what happened to these chips when the place was sold. If they did, I am sure the chip would have went for much higher dollars.

Finally, many of the Ebay bidders who are knowledgable want the chip for nothing or next to nothing. They quit bidding if they can not steal it with the attitude the next chip is just a click away! Hope this helps. Best, Jim