A few titles in the Ava Lee series by Ian Hamilton are $2.99 each at Kobo US (coupon/VIPable). Unusually, there are more titles on sale at Kobo US than Kindle US - only two are $2.99 at Kindle US, at least as of now...
The King of Shanghai, #7
Kobo US:
https://www.kobo.com/us/en/ebook/the-king-of-shanghai
The Imam of Tawi-Tawi, #10 per
Fantastic Fiction, #11 per Kobo
Kobo US:
https://www.kobo.com/us/en/ebook/the-imam-of-tawi-tawi
The Goddess of Yantai, #11 per
Fantastic Fiction, #12 per Kobo
Kobo US:
https://www.kobo.com/us/en/ebook/the-goddess-of-yantai
Kindle US:
https://www.amazon.com/gp/product/B07HHKX9F3/
And also,
Fate, which is the first in the spin-off Uncle Chow Tung series
Kobo US:
https://www.kobo.com/us/en/ebook/fate-65
Kindle US:
https://www.amazon.com/gp/product/B07J2VYFZL/