Many people have asked me why I don't sell my books in the Kindle store. Most readers don't know how onerous the terms are. For any books over $9.99, the Kindle store wants 70% of the proceeds. For books between $2.99 and $9.99, the Kindle store wants only 30% of the proceeds. What it means is that the $9.99 cover price and the $24.95 cover price nets the same profits, so I was unwilling to sell my books at the Kindle store for that reason.
However, now that I've got a second edition of the book out, I'm selling the first edition at the Kindle store for $9.99. My guess is that most people would prefer the second edition (when you're negotiating compensation, the extra $15 is easily justified by the improved second edition). However, if you're a poor student or just want to buy the book for someone as a gift and are cheap, well, the Kindle 1st edition is easy and convenient.