Free Fall (The John Ceepak Mysteries Book 3), by Chris Grabenstein, is currently $1.99 at Amazon, Kobo, etc. It's an Open Road Media sale, so it's good for today only -- sorry for the late notice! The regular Kindle price is $9.99, so this is a good deal.
https://www.amazon.com/Free-Fall-Joh...dp/B07B68R52N/
I've read and enjoyed all of the books in this series.
The first book in the series, Tilt-a-Whirl, appears to be permanently priced at $0.99. I think it would be better to start with the first book to have the characters introduced, but it's less necessary to read the rest of the books in order.