These guys are trying to scam somebody:

http://www.amazon.com/gp/offer-listing/1589943007/ref=dp_olp_used?ie=UTF8&qid=1282255139&sr=1-1&condition=used

And it is a USED item. Sheesh.

Holey Toledo! Buy two! No! Buy three, just to be safe!

Heck, if they'd be willing to buy at a third of that price so they could resell, I'd sell them all of my Mountains of Madness sets.

Assume incompentence before nefarious. They probably meant to type 9.99 but somehow hit a few extra 9's without noticing it.

I remember seeing an asylum pack on eBay for over $1000. And since it was an even dollar amount I just chalked it up to somebody forgetting their decimal point.

Sometimes a tiny dot makes all the difference.

I remember a friend, who is often selling stuff on ebay telling me, he sometimes did this intentionally.

It serves as a placeholder/reminder for the seller, nothing more. It's not meant to be a real offer.

I remember one day around 2002, I wanted to buy a classic book from Sid Sackson ('A Gamut of Games', edition 1992, 30 $ on retail price), there was an offer on Amazon for... 1000$ The book was out-of-print since a few weeks only because I saw it available previously but was waiting to add more suggestions on my buy list. So my conclusion was that that the rationale behind this price offer is that someone tried to sell it to some collector ready to put an insane amount of money on it. Even today, the book has still not be reprinted (a shame) and the offers on Amazon go up to 170+ usd.

I saw a similar phenomena for the AP 1 'The Spawn of Madness'. After months of monitoring eBay in 2007-2008, the first time I saw this AP to be sold (summer 2008, after the CCG was dead and a few months before the LCG core set was released), the item was won for 52 euros! (and the euro was ~1.40 usd at that time).