Far worse than the increased prices are the decreased availability of scholarly books. Many classic historical and philosophical works, which were widely available in paperpack at reasonable prices in the 50's through the early '80s, are now out of print and hard to find.
I was recently looking for some things in the Columbia University bookstore and some bookstores right around Columbia and could not find such classics as Edmund Wilson's Axel's Castle or Ernst Cassierer's The Philosophy of the Enlightenment. I could find no criticism of T.S. Eliot -- I mean I know he's not at the height of his fashion, but nothing....?
I hesitate to post this because wider knowledge will drive up the prices of all the obscure books I buy there, but have you tried "abebooks.com"? They're a lot like Bibliofind was before Amazon took it over, with a heavy concentration on stores in the U.K. Between those two places (with an occasional look-in at Half.com), I don't think I've been unable to find anything I've been looking for for about two years now. And my weird literary requirements make Eliot criticism look as rare as Harry Potter.
Give it a try.