Last week I downloaded Kindle for the PC from Amazon.
My laptop came with Toshiba Book Place (TBP) already loaded. I used it to download some of the free e-books at Google Books. TBP was okay, though somewhat clumsy. Then a few months ago I downloaded an upgrade to TBP, and did not like at all what the "upgrade" did to the appearance of my TBP library.
I really like what I am seeing with the Kindle for PC. TBP had a few minor features Kindle does not have, but the Kindle functionality and appearance wins hands down.
Up to this point all I've downloaded for my Kindle library has been free stuff such as this The English Standard Version of the Bible. There are a number of $ 0.99 collections available at Amazon, and I am looking forward to expanding my e-book Kindle library in the future.