Mick Sussman has a really interesting (to me, at least) post at the Times's Paper Cuts blog about the phenomenon of used books that seem to be vastly overpriced on Amazon - a post prompted by his attempt to purchase Rick Perlstein's unjustly out-of-print Before the Storm, which is currently priced at $131.09 for a paperback, and (oddly) only $89 for a hardcover. I bought Perlstein's book used myself, a couple years back, but at the point, if memory serves, it was going for a much more reasonable price. (This was before Nixonland came out, of course.) I had a similar experience to Sussman, though, when I needed a copy of Kevin Phillips' The Emerging Republican Majority; I don't remember exactly how much I spent, but it was something far more obscene than the $47.86 that it currently takes to get a copy.
In the spirit of authorial solidarity, incidentally, I urge anyone who wants to read Before The Storm - which is well worth your time, as I'm sure I've mentioned before - to wait until next summer, when Nation Books plans to bring it back into print. No matter how high the price of a used copy rises, the writer himself doesn't see a dime of it.