Depends on where you look. There's a thriving community online which OCRs and distributes books for free. I've been downloading books that I own and want to read, but would be inconvenient to take the book with me. I still buy books when I can afford to, but paperbacks seem to keep going up in price, and I long ago stopped buying hardcover. (Not counting books like Harry Potter and the Order of the Phoenix which are only available in hardcover, the last hardcover I bought was Crown of Swords - $40 plus tax)
I can remember when I used to take a backpack of books with me on vacation - now I just take my PDA.