I've mentioned before how much I like the Pot Thief mysteries by J. Michael Orenduff, but they are Open Road titles so they go on sale a lot, and I don't post anymore. But right now the first two collections, with three books each, are on sale for $3.99 each, and that's a chance to get two-thirds of the series in one fell swoop, at a pretty good price, if you don't already have any of them. (The collections do occasionally go on sale for $2.99 each if you want to be more patient, but I've not seen both on sale at once before...)
Volume One contains
The Pot Thief Who...Studied Pythagoras,
Studied Ptolemy, and
Studied Einstein. Volume Two contains
The Pot Thief Who... Studied Escoffier,
Studied D. H. Lawrence, and
Studied Billy the Kid.
Kindle US
Volume One:
https://www.amazon.com/dp/B072542KKF
Volume Two:
https://www.amazon.com/dp/B07CMK264W
Kobo US
Volume One:
https://www.kobo.com/us/en/ebook/the...ies-volume-one
Volume Two:
https://www.kobo.com/us/en/ebook/the...ies-volume-two