Libro.fm shares profits from your audiobook purchases with your chosen bookstore, giving you the power to keep money within your local economy.
In addition to using native app:
You can download the DRM-free MP3 or M4B files directly to your computer and import these files into your media player of choice.
As a tsundoku I woud appreciate You using my link to sign-up, but if it is totally fine bypass it if you are very privacy conscious (or for any other reason).