N-Wing says According to this and this, the two biggest book costs are distribution and printing, both of which are essentially $0 for electronic formats. In a very small sampling, some ebooks were cheaper and some more expensive than paperbacks. Lets mention this greed thing again.
My reply: I'd have to know which ebooks you're referring to before I could posit a reason for the price difference. A few publishers price electronic versions and print versions exactly the same so as to not undercut print sales. However, many publishers do give their e-books lower prices than their print books.
But the price points are a bit irrelevant, because ebooks have largely been failures except when you're dealing with romance, erotica, porn, and technical documentation. Romance/erotica/porn readers tend to consume a whole lot of books, and e-books are cheaper and psychologically easier to discard than paper books. Plus, e-book readers provide the ultimate brown paper wrapper to prevent the other people on the commuter train from seeing garish covers featuring vast tracts of mantitty or heaving cleavage. Technical documentation ebooks sell well because the people who buy them mostly need tech books for quick, specific reference and don't intend to read large sections in one sitting as they would with novels or long nonfiction.
But, sales show that most readers of other forms of fiction and nonfiction prefer to buy books as physical paper objects. This may change in the future if better, cheaper ebook devices become available, but so far, the fastest way to produce a book that almost nobody will read is to release it in ebook format. Yes, some people enjoy reading long works on their computers; most demonstrably do not.
My first story collection was an ebook entitled Blood Magic which cost $3 (which fairly represented the cost of cover art, layout, etc.) as a download on Fictionwise and $6 in CD format (which fairly represented the additional labor/materials involved in putting the CD version together). My current book is a trade paperback that costs $18.95 at most places. You would think that a $3 collection would sell way better than a $19 collection. However, in the 6 months that Sparks and Shadows has been available, it has vastly outsold Blood Magic, which was available for 5 years. I've heard from a lot of other writers who've had similar results. I've also heard from publishers who got started doing electronic editions but who turned to print after they kept getting messages from customers who said they'd buy more if only the books weren't so expensive to print out.