I purchased a Kindle from Staples a couple of weeks ago, on Friday the fifteenth.
Why Staples? I prefer buying physical objects in person, though I will admit that that's somewhat odd given that the object in question was a Kindle. The two brick-and-mortar stores that currently carry Kindles are Target and Staples. Now, I like Target, and dislike Staples, but I'd called around to a number of Targets and they didn't have any in stock. The buying experience wasn't the best, but I ended up with a wifi graphite Kindle, so I was happy.
I loaded it up with mostly free books that evening, and the next morning purchased Cryoburn by Lois McMaster Bujold. I plan to review Cryoburn soon, but for now, I'd like to talk about some different options for purchasing ebooks.
Baen Books is my favorite commercial site. The Baen Free Library has one or two books each from a large number of their authors. This is a great way to sample an author, and if you like it, the author's other books are just a quick click away.
They sell their books through Baen WebScriptions, which is a pleasure to use. You can pay with a credit card, or you can use your credit card to fill a micropay account. I like the micropay account, I always feel a bit guilty using a credit card for small purchases, since the transaction fees hit the merchant pretty hard.
The books are available in a wide variety of formats, and all of them are DRM-free. And you can set it up to email the book to your Kindle email, so it just pops over to your Kindle as easily as if you purchased it on Amazon.
The price is good as well, the prices seem to run between four and six dollars. To me, this is a reasonable price to pay for an ebook, and it's low enough that I don't mind paying it to replace books that I already have physical copies of.
Amazon is the obvious place to go, of course. And they have a huge selection, running the full gamut of free, cheap, reasonable, and overpriced. Their books are DRMed, as well.
The Gutenberg Project has a huge catalog (34,000+) of copyright-free books, and they now support the Kindle format directly. This is an amazing project, if you haven't heard of them before, visit the site even if you don't have an ereader.
Manybooks.net has most of the Gutenberg books, and well as books from other sources. Of most interest to me are the Lovecraft books.
Another place I've purchased ebooks is fictionwise. They have some titles that aren't available elsewhere. Look for the "MultiFormat" label, those books aren't DRMed and therefore can be read on the Kindle.