The Overdrive service is available through your local library, so find that library card you haven't used in years. Each library purchases titles they feel meet the needs of their patrons. So a book available in one city may or may not be available in another. Overdrive patrons check out and return/renew downloadable titles, just like regular print books. For popular titles you may find yourself on a waiting list, also like using your local library.
As for the service itself, since you are not making purchases, Apple's licensing rules allow for in-app downloads. Dixon demonstrates how to search, download, and play books and magazines produced by the Library Service. You can also read braille titles using this app, a feature Dixon describes in depth in Chapter 3: Reading Books in Braille.
Most eBook iOS apps work with braille displays, but each takes a slightly different approach, so your settings may need to be changed to get the output you desire. Dixon devotes an entire chapter to using a braille display with each of the apps mentioned above. She also describes how to search and download .BRF books from the National Library Service and read them using the BARD Mobile app, which was optimized to offer an excellent braille reading experience.
The final chapter of The Abundant Bookshelf offers a list of other sources of both audiobooks and eText books. Notable among these are Blio, Project Gutenberg, and Google Books. For each she offers tips on downloading books, many of which are free, and working with the app interface.
Downpour offers two features not available from Audible or most other sources of downloadable titles. First, Downpour titles are available in non-DRM (digital rights management) MP3 formats. This means you can listen to these books using the player app and device of your choice. Second, you not only can purchase titles using a membership or subscription plan, but you can also rent titles for at least 30 days. 2b1af7f3a8