A couple of Open Road titles that haven't been on sale too much in the past, or at least I haven't noticed them on sale myself...still traveling so just titles and links....both $1.99 (and couponable/VIPable at Kobo)...
Dragon's Teeth, Lanny Budd #3, Upton Sinclair
Kindle US:
https://www.amazon.com/dp/B018V77HZ4
Kobo US:
https://www.kobo.com/us/en/ebook/dragon-s-teeth-7
Death in the Wasteland, Insp Littlejohn, #37 (in somebody's schema), George Bellairs
Kindle US:
https://www.amazon.com/dp/B07CMD3H8M
Kobo US:
https://www.kobo.com/us/en/search?Qu...the+Wasteland+
And then if you want a bunch of Anne Perry/Charlotte and Thomas Pitt, and don't already have the individual books, here are some omnibuses at good prices:
The Charlotte and Thomas Pitt Novels Volume One: The Cater Street Hangman, Callander Square, and Paragon Walk, $2.99
Kindle US:
https://www.amazon.com/dp/B07CNB8NFS
Kobo US:
https://www.kobo.com/us/en/ebook/the...els-volume-one
The Charlotte and Thomas Pitt Novels Volume Two: Resurrection Row, Rutland Place, and Bluegate Fields, $4.99
Kindle US:
https://www.amazon.com/dp/B07G7VYSR4
Kobo US:
https://www.kobo.com/us/en/ebook/the...els-volume-two
The Charlotte and Thomas Pitt Novels Volume Three: Death in the Devil's Acre, Cardington Crescent, Silence in Hanover Close, and Bethlehem Road, $4.99
Kindle US:
https://www.amazon.com/dp/B07G7RDK5P
Kobo US:
https://www.kobo.com/us/en/ebook/the...s-volume-three