Amazon has a large number (but a fraction of the total available) of Oxford University Press'
A Very Short Introduction series marked down for only 99 cents each! I think each one of these has a regular digital price of $5.19.
What are the
A Very Short Introductions? Well, think of them as the Charles River Editors book(let)s on steroids. For one thing, they are not all that short--the ones that I spot-checked were all well over 100 pages long.
Because it's late in the night here, please allow me just to give you
the Amazon webpage where you can find all of the marked down ones (as well as all of the rest), instead of giving you links to all of them individually or even listing all of the titles. The books are sorted by price, low to high.
Now here's something else important. Several of the ebooks have Whispersync narration available! The ones that I spot-checked were all $3.99. That's just for the narration, not the whole deal. To find out the total price, just add 99 cents to whatever the price is for the Whispersync narration for the ebook. Oh, and for some reason you won't have the option to filter out via the menu on the left side, as you usually do, the hits that have the Whispersync companions. So, either look just below the "Buy Now with 1-Click" button for "Whispersync for Voice-ready" or do a search (Ctrl + F in Google Chrome and Internet Explorer--I don't know about the other browsers)--using "Whispersync" as the search term should be good enough.