I've got an original printing of my novel, "The Oort Perimeter" which I did through Amazon. Since my time with them was generally a flop (never, ever publish with Amazon. They're epic level putzs.) I ended up switching over to my current publisher, who has done an awesome job getting me noticed and books sold. Ok, they're all print books at this point as we only recently got to the whole ebook thing, but still, I'm selling books.
Anywho, in regards to the printing that Amazon did for me, there's only 207 of those original "blue" cover Oort Perimeter copies in existence. (I've still got some left if anyone wants a couple) Well, since that's all that were ever printed, and will ever be printed of the blue cover edition of the book (Oort Perimeter will continue to be offered indefinitely through my new publisher. This only covers the ones originally done through Amazon) the "in the wild" market value of the book has already gone up quite a bit. It started out at like $39 a few months ago (and this for a book I'm still selling for $16 a copy till my supply of blue oorts is gone) and is now ranging between $99 and $165 market value for collectors.
And this is merely based on my current popularity, rarity of this edition of the book (ie, the 207 total copies), and popularity of the book itself. I'd say that's not bad. If I've only been actually publishing my works since August of last year, and it's now 7 months later and that particular limited edition printing is already worth that much, that's a good sign that both I as a writer, and my books, are both taking off.