It's only what certain merchants are charging for idiots who want the book right now, not necessarily what people are willing to pay. Considering the options (DriveThru, scans, waiting for a normal auction, finding a game store owner who's getting rid of merch, etc.), one'd be a fool (or have too much many) to blow that on a book with a decent chance of being superceded within the next two years.
 And Twilight's not even the scary one. Caste book Night...yeow.