Um...it's not the papers and ink that are expensive...it's the ideas & all other sorts of things that come with the books that are expensive.
That's why exercise books are cheap.
Depends, I find the average paper back cheap.
I find graphic novels, collaborative works and hardbacks more expensive. It also depends on where you shop... if you want a classic, hit up a second-hand book store.
If you want the new releases try ebay.
Books are also expensive because many are translated, shipped from abroad or (in the case of informational ones) they require a great deal of research, and they have to spend money themselves to gain access to archives and people.
But I do agree that they are overpriced often, hence why we have libraries