As soon as you place an order for a Kindle at Amazon or through an Amazon marketplace seller you'll get a Kindle account even though you don't have or have activated a Kindle. Go to the Kindle book section and in my case it said Dallas's Kindle. Then I saw an order for a relatively cheap new Kindle through an amazon marketplace merchant so I purchased that one and cancelled my original purchase through amazon and I saw on my Amazon account Dalla's Kindle and Dallas's second Kindle. I downloaded books for both of them. Only problem was the second Kindle I purchased turned out to be a sham transaction so I repurchased through Amazon and guess what, when I went to download another book it said Dallas's Kindle, Dallas's Second Kindle, and Dallas's third Kindle. Well the story only gets worse because I found a relatively good deal on Ebay and purchased that Kindle on the spot. When the Kindle came I again cancelled my most recent Amazon purchase and registered my new Kindle with Amazon, so when I went to the Kindle Bookstore, I saw Dallas's Kindle, 1, 2, 3, & 4 and I had downloaded books four all four kindles. I thought I might have a problem until I went to the manage my kindle account and saw that I could send any of the books that I had ordered for the phantom Kindles that never happened to Dallas's 4th Kindle. So I guess in my case 4 times was the charm.
Sorry for the long winded story but bottom line is start ordering today especially the free ones. The freebie offers on some books may end before you get your Kindle so feel free to order your books now. You'll definitely be able to transfer them to your new Kindle when you register it.