OReilly’s EBooks

I have purchased several books from Oreilly’s EBook store. They are running get 1 free for every two books purchased promotion. Also they guarantee new editions of ebooks you have already purchased for only $5. This prices are the cheapest ones I have find on a ebook store. But they are most of these ebooks in iPhone o Android market for just $5. This is not fair. After purchasing several books, I have searched OReilly Coupons from Google and find some super coupons which reduce price of the book to $5, or 50 percent. Search for some coupons before buying from EBooks from OReilly.