When the last one was released, a lot of bookstores had slumber parties, as the book was available at 12:01 a.m. Amazon's price seemed reasonable - most new releases are $25.00+.
I paid $21.96 at barnes&noble.com; that includes shipping. On their website, they have a couple of little clips from the books. This one is longer that the Goblet of Fire! I was surprised by that because I kept hearing that is was going to be more along the lines of the 3rd book as far as length is concerned.