I think it depends on what kind of stuff you like to read. If it's mostly best-seller type stuff, then yes, you're going to pay $9.99 or more per book.
But if you like indie authors, it's a different story (pardon the pun). I just finished reading
The Book of Adam. I got it from Smashwords. I thought it was one of the best books I've read in a long time. The cost? Zero

! There are other books at Smashwords that are getting good reviews (e.g.
Radium Halos). Cost? $2.99. (Of course, there's some pretty awful stuff on Smashwords too). But I'm keeping my fingers crossed that this more direct and cheaper channel between authors and readers will become more widespread and easier to use in the future; and that the good quality will choke out the junk stuff over time!
And if you like classics, there are thousands of them available for free download here at MR!