You could try www.openculture.com - lots of free audiobooks and lectures. Also there’s librivox.com - free audiobooks in the public domain. And also The Gutenberg project - again books in the public domain, but some good - and free classics that you can download and listen to.
yeah, I’ve grabbed a few things from Librivox already, but I didn’t know about openculture.com, I’ll have to check it out.
Thanks.