[sirbruce]

The problem is the sentence is poorly written. They probably meant:

Requires you to buy a limited number of books at the Sony store.

Now, the problem is, does "a limited number of books" modify requires, or the Sony store?

If they mean that you're required to buy a limited number from the store, but then you could buy more elsewhere... well, that's just false. There's no requirement to buy, say, 2 books from Sony before you can buy or get for free books anywhere else. That wouldn't make much sense.

If they mean that you're required to buy from store *which has a limited number of books*, that would make more sense as a marketing point. You're commenting on Sony's limited selection. Notice how they do *not* make the same claim of the Kindle, even though you could, because the Kindle has a much greater selection. Thus, what they meant was that the Sony store has a limited selection from which to buy. Clearly.

However, this is still deceptive. While they didn't use the word "requires" for the Kindle, the implication is the same... you have to buy from those stores. For Kindle it's Amazon. For Sony it's Sony and it's limited. For JetBook: You get books from the Internet for FREE.

And that's not only deceptive because you can get all those free books for Sony and Kindle too, but it also implies that virtually any book can get gotten for free, which is a lie unless it's illegal.

If they had ibstead fully disclosed something like

Amazon: buy new books from a wide selection and as well as free public domain books
Sony: buy new books from a limited selection as well as free public domain books
JetBook: can't buy new most new books, mostly get free public domain books

Well that's just not as impressive, now isn't it? JetBook comes off looking worse, not better. (Of course there are more recent free books you can get, and now I suppose you can read buy new non-DRM MOBI books for JetBook, but these are edge cases.)