That hardware margin must be looking pretty thin right now. Not only were they forced by B&N to lower the price of the Kindle, it doesn't take a rocket scientist to see that the iPad is cutting into dedicated reader sales right and left.
So how much longer can Amazon afford to subsidize the $9.99 ebook prices which, as Rupert Murdoch said earlier this year, "devalues books"? I think the trend towards higher prices has already started but nobody seems to have noticed.
It's far from scientific but as I write this post I see 2 of the top 10 paid titles on Amazon's Kindle bestseller list are priced at $12.99. The product pages for each, btw, include Amazon's not-so-gentle reminder to customers that "This price was set by the publisher." I don't recall anything over $9.99 in the top 10 a year ago. 2 out of 10 is interesting, but 6 out of the top 15 and 8 of the top 20 are priced higher than $9.99.
FWIW, even I've become more willing to pay more than $9.99 for a Kindle or iBooks edition. Two of my most recent purchases were $12.99, so even a tightwad like me is coming around. And even though I'm no longer locked into $9.99 as a ceiling, I comparison shop to see who's got the best price. More often than not they prices are identical, but every so often I find a difference and go with the lower one.