US Audible is doing
a sale for various series, though it's Audible members only (and you have to be a US member, which I happen to be for some reason). It's only on for another 36ish hours. I got book 2 and 3 of the
Lady Astronaut series. I wish I had lots of money to spend on it because there's tons of good stuff, including Martha Wells, Octavia Butler, Tolkien, and more. Still eyeing the Murderbot series, but I really can't afford it.

(Kind of funny since I'm always complaining about promotions being US only.)
[Update: I had to update my debit card details so the Lady Astronaut books didn't go through, and I ended up getting all of Murderbot instead. Woo!]