With almost any popular, still-under-copyright book, this is what the pricing looks like on Amazon:
http://www.amazon.com/Harry-Potter-Sorcerers-Stone-Book/dp/0...
Paperback: 8.79 dollars. Kindle: 7.99 dollars. Used: 1 cent. Used via Amazon Prime: 3.98
To save NINETY CENTS you get an arguably inferior copy that you cannot resell, pass on, share, touch, or truly experience. No, thank you. And don't forget that your Kindle cost a hundred dollars - you'll need to buy a hundred and eleven such books before you're actually "saving" money.