I would never buy a paper version of a book that I have purchased in e-book format with one exception as noted later. As far as purchase of later books in a series when the the first in the series (or the first few) have been offered free as an inducement to make me take a look at an author I don't know? Sure if I liked the first few.

Unlike some I am not so inclined to whine about the cost of an e-book that I know I want. “As in why is the price the same as the paperback, etc.?” Generally the discussion is over an amount less than the purchase of a fancy drink at Starbucks. If I don't want to pay that then I did not want or need the book that much anyway.

When would I buy a paper version when I already have the e-book? When the e-book is crap. This is usually not due to the markup (note I buy e-books in epub format or immediately convert to it). Provided that is that the markup has followed what I feel should be cardinal rules: 1) keep markup to a minimum. Every tag should serve an essential purpose. I see too many books with all sorts of unneeded span tags. 2) Put all style information in one external stylesheet. If these rules have been followed it is not that hard to fix it to an e-book I can enjoy.

No I am talking about bad data: typos, misspelling, or even missing content. Then I curse the supplier for tricking me into buying a worthless product and, if it is a book I really want, buy it in paper.

Sorry for the rant but I just made such a worthless e-book purchase.