So what kind of benefits are rather costly for the average book...well, here are a few...
* full color printing
* permission fees for song lyrics
* permission fees for reprints of artwork
* large excerpts from other authors
* creative formatting or binding
And let's not forget E-books...
* adding pictures
* adding any graphic
* adding music
So let's just remember, folks buy books for what they say. And lots of book benefits (like anecdotes and humor) are free!