I've had a Kindle for a little over a year now and I've found that I've read a lot of books which I wouldn't have usually considered reading. I get the free book update e-mails from EreaderIQ and I download whatever book titles take my fancy. Start to read something, if I like it keep reading. If not, then I delete it.
I've read books from local authors about local history, various travel books such as by people who have gone for a ride to India (You've Gone Too Far This Time, Sir!) or a walk across France (Best Foot Forward), books from people writing about the job they do (Confessions of a GP, The Checkout Girl), murder mystery books with a religious slant (Lie Down in Green Pastures).
I could go on. Many of the books were free, or low cost (under £2) at the time I brought them. Due to the way that the books are sold, it is easy for publishers to reduce or make a book free for a very limited period, often a couple of days. So you can get books that normally sell at around £7 for free, if the publisher decides to promote the book.
I don't know if the same thing occurs with other formats of books but I think that because Amazon are the only place you can buy books in AZW format for Kindle, these 1 / 2 day promotions can be run by publishers to attract interest in books by a certain author, thus encourage readers to read other books by the same author.
I've not paid for a book for about 4 months... I hope to get an amazon voucher for xmas from my sister, so will use that to pay for some books over the next year.
Suppose what I'm saying is that as long as you are not that bothered about reading the latest books by well known authors but instead are prepared to give other authors, including those who self publish a go, then you can get many books for free or low cost.