On the secondhand market, recent fiction is hardly worth selling. It might get published with a hefty pricetag, but what happens is that people read the book and a few days, weeks, months or years later decide it's not a keeper and pack up a box with all the other similar and try to make a few bucks off the local secondhand bookdealer.
Usually by this time the book has been out for a while in paperback and the market for new buyers has been satisfied. A lot of people have read the book in libraries. So there aren't as many people wanting to read it as there was.
The poor old bookdealer is faced with a lot of people wanting to sell a book that few will buy. Of course the value goes down. It's a matter of supply and demand.
So some recent fiction paperback novels turn out to be worth only a few cents, despite the original buyer paying many, many times that when new.
In my line of business especially, there isn't much profit in selling recent paperback fiction. If I bought all available to me, even at a few cents each, and tried to sell it at my minimum price of $US2, I'd go broke. I don't even have the luxury of a bargain bin out the front of the shop, because I don't have a shop.
BookCrossing is my bargain bin.
Pete, online bookseller trying not to go broke