Indie author J. A. Konrath has been on a roll recently:

I just checked my last royalty statement. Rusty Nail, that book I worked so hard to promote, has thusfar earned me $42,000. This includes all of my hardcovers, paperbacks, ebooks, and foreign editions, combined.

With self-publishing, in a single month, I was able to earn the same amount of money it took me four and a half years to earn through traditional publishing.

And that’s only 20% of readers currently reading ebooks.