There have been a number of other threads too, regarding these items, do a search to find even more info! :-D :-D
I have the Nook, and LOVE it....
I can get books from the library on it easily, which is why I chose it over the kindle.
It seems that, like anything else, an ebook will be more or less expensive at one or another site, from day to day... so price of new books isn't something that I worried about. If I MUST have a book NOW NOW NOW, I will pay what it costs....if I just want it, I can wait for the price to fall or for the library to get it!
You will love your ereader, whichever you end up with