Someone mentioned, a couple of years ago, that Routledge Publishers is into Open Access in a big way. I think that information about the
free ebooks available through their Open Access program bears repeating.
At least some (but still a huge number) of Routledge's Open Access titles are available as Kindle mobi's at Amazon. I suggest that you start your mining for them at
this webpage at Amazon. Beginning at
that webpage, the Routledge titles are sorted by price, low to high.
There is at least one title, the first one listed, which is available as an Audible audiobook. Interestingly, the price for the audiobook alone is $14.95, but if you "buy" the ebook, you can get it for $7.49. I don't know if that situation holds true for other titles which have the Audible audiobook format as options--there appears to be no way to find such books other than to search each webpage.
Most by far, if not all, of the titles are non-fiction; thus, the reason for posting this information on the "Non-Fiction" thread.
Thank you, Routledge!