PDF as gateway

http://wilwheaton.typepad.com/wwdnbackup/2009/02/in-which-an-electronic-version-of-sunken-treasure-goes-on-sale.html

I won't belabor a retelling of the story you can simply read, but here's the short version: Wil Wheaton releases a novel through Lulu print on demand. Decides to also release a $5 pdf of book. Pdf sales quickly match physical sales. Then physical book sales increase as well.

Lock grandpa in the attic, giving it away free (or cheap) online is an entirely viable business strategy.