If you like the Valdemar series (and spin-offs) by Mercedes Lackey, or just want to give it a try, there is a Humble Bundle available right now with 37 books for only $18. Which is a wild bargain, even if you already have a lot of the books! It’s way too many books for me to type all the titles, but there’s a link to the webpage for the deal at the end of this comment, and you can check it out for yourself!
The way Humble Bundle works is that you can choose one of several different prices, and that determines how many of the books in the Bundle you will receive. In this case, you can get 2 books for $1, or 13 books for $10, or you can get all 37 for $18. The books are then redeemed via Kobo – you will receive a code and instructions after you purchase. The redemption is a little bit complicated, but totally doable if you follow the instructions. It’s also worth noting that you also have an opportunity to pay a little bit more, and have the balance go to a charity of Humble Bundle’s choosing. (Info about which charity is currently receiving the donations from this Bundle is on the lower right side of the Bundle webpage.)
Here’s a link to the Bundle page, and my thanks to @PennyDreadful on the Mobile Read forums, whose post alerted me to this deal. Today is June 7, 2023 and the Bundle indicates it’s available for 16 more days.