Recently, I took to checking out the free ebooks on Amazon, and there is a vast treasure trove of free ebooks available for download at no cost. For example, a very enjoyable sci fi novel is The Phoenix Conspiracy. The characters and plot are very well developed and I was absolutely sucked into reading it straight through, then purchasing its sequel. And very anxiously awaiting the 3rd book.
I suspect that's how the authors use this platform for sales, the first book in the series is let go in the wild free, and if the reader enjoys it, will definitely want to continue, hence the need to purchase the rest of the series.
The kindle platform is one I really enjoy. I think I have lost interest in gadgets years ago (hello, pda). But this is one gadget that I don't regret purchasing. First, the e-ink is just damned good for reading with compared to real paper. The battery life is insanely good as well. I like the fact that kindle ebooks are downloaded in an instant, and I don't have physical books cluttering up my room. Wolf knows how many books that don't have digital versions are stacked up 10s high on my shelves.
One additional feature that's really nice is sample content; a short preview of the ebook to check out before purchasing.
Technical books OTOH are what I generally do not want on the kindle as I want it on my lap or across my desk as I work on 'em. Stuff like math and programming texts, ewww, no digital stuff. I do tend to mark up such texts with a pencil as well, so paper is the way to go for these.