Titles in the Robert Amiss/Jack Troutback series by Ruth Dudley Edwards don't go on sale very often, and now there are three price drops at the same time, all to $1.99 in the US. Oh, and they are discountable at Kobo US.
I've quite liked this series, in spite of not really agreeing with Edwards' politics, except for the last couple of titles, in which the politics took more of a prominent role. But the first many titles were, in my opinion, a quite nice mix of dry British humor, some suitably puzzling mystery plots, and sharp enjoyable writing. And of course, your politics may be different than mine, so YMMV...
The English School of Murder, #3
Kindle US:
https://www.amazon.com/dp/B07VNH25G7
Kobo US:
https://www.kobo.com/us/en/ebook/the...ol-of-murder-2
Ten Lords A-Leaping, #6
Kindle US:
https://www.amazon.com/dp/B07VPKS75B
Kobo US:
https://www.kobo.com/us/en/ebook/ten-lords-a-leaping-8
The Anglo-Irish Murders, #9
Kindle US:
https://www.amazon.com/dp/B07VLBQVTN
Kobo US:
https://www.kobo.com/us/en/ebook/the...rish-murders-3