I am still at a loss for this one. Not sure even the silly fashion designer model that Nintendo did as a stunt (though sold in their New York location I believe) would probably clock that.
I equally can't imagine people are in a hurry to get their hands on that cartridge either. Rare betas and unreleased games sure I could expect prices to go a bit higher.
Also zoomed in on one of the shots.
The ripples/"cracks" in the right hand side makes me wonder if this is not a sticker. If it was an official different mould (they would have stuck a little standoff in the mould to make something indented easily enough) then possibly maybe it could be desirable to someone maybe. It is only mcdonalds though.
Don't think it would be a developer DSi (those do command a bit) or some super hackable one (things are kind of open enough these days).
Guess it is either one of those throw out a crazy price type auctions (you see that one often enough when someone assumes rare= valuable) or I am seriously underestimating the collectability of mcdonalds stuff (I have seen stuff for automotive, for coca cola, for beer, for tobacco and vintage kitchen stuff but mcdonalds is a new one).