i always get my free books from there now! they've got a version for teens and kids too..
some of them are evil.. They're good books but in series so they give you #1 for free, then you end up spending $3 to buy #2 and #3.. Xd
but yeah.. Amazon's probably the cheapest place to get books.. I had a look at one of the ebook stores that sony recommended, and all the books are as expensive as paperbacks and has a horrible browse function...