When you buy a book, you are not paying for the words, but the moment.
All books get discounted in time and almost all get discounted almost immediately.
If you want to read a new book on the day of its release, then you have to pay for that priviledge.
If you can wait a week, then the price will go down. If you wait six months you can buy the book on clearance at a b&m bookstore for almost nothing. Wait a couple of years and you can buy it at a yardsale for ten cents.
Or, wait a few months, and read it for free at the library.
While ebooks offer a somewhat different method, they, too, will eventually be cheap in whatever format.
So, really, either enjoy the thrill of a new book as soon as possible, or if price is the price concern, just wait.