But, just to be clear here, there is nothing illegal about charging money for a public domain work. It may sound a little underhanded and sneaky, but really it's not. If someone doesn't realize that, for example, the older books by P.G. Wodehouse are in public domain, you really are under no obligation to tell them. Knowledge is power.
Many companies take public domain things, such as maps and claim copyright. Well, they can CLAIM copyright, even threaten you, but they can't HAVE copyright. And so, why would I pay 99 cents for a book that I could get, absolutely free, from a site like Gutenberg?
Convenience. The file I downloaded yesterday into my Nook contained ten books by P.G. Wodehouse. Yes, I could have downloaded all ten books, copied them into Adobe Editions, then transferred them to my Nook. It would have only taken me about fifteen minutes. But by paying the nice people at Barnes and Noble 99 cents, I downloaded them in seconds and was reading right away.
By the way, Barnes and Noble doesn't claim copyright on these books. They are public domain. I was glad to give them 99 cents for the convenience. And that's what I paid for - convenience. I like my Nook and I like Barnes and Noble. Nah, they don't pay me anything to say this, I wish they would. It's just nice to know that they know how to do it right.
Knowledge is power. And it's worth 99 cents to me.