Never bought an e-book, as I have no reader or plans to get one.
No free books, although I've bought books at a nominal cost from the library sale tables if they look interesting. I get 'free' from the library, a major source of 'books I want to buy'.
I buy 50 - 100 books a years. Chiefly bricks-and-mortar.
I've bought 4 self-published books, ever, that I know of. Two were fiction, I know the authors, knew what they were about, thought I would like them, and I did. Two were non-fiction (my real reading preference). One was well-designed and produced, and thoroughly described and explained a new technique for a craft that I was interested in (with excellent, step-by-step colour illustrations). The other was a piece of junk, that took a simple concept, added no new information, was sloppily put together, and had badly hand-drawn (scrawled, really) pattern pieces that would have to be re-drawn to be useable. If I could have seen a sample, I wouldn't have touched it.
That to my mind, is what a self-published 'review' site needs: mandatory 'Look Inside' feature, and not Amazon's first few pages, that a publisher can game by using the copyright page, and title page as half of their quota.
I don't know if Amazon charges for 'Look Inside', but it should be mandatory with a listing:
A good big chunk of actual text, the table of contents, a sample of any illustrations, and the index/bibliography (if any). A reasonable sample and I don't need to read other people's opinions.
(I read reviews for 'spoilers', actual information on the plot. I assume that the rest is subjective nonsense.)