The books in SW Perry's Jackdaw series go on sale a lot, so I usually don't post anymore. But it is unusual to see all six, including the newest one, on sale at the same time, in the UK, for £0.99 each. Titles include:
The Angel’s Mark,
The Serpent’s Mark,
The Saracen’s Mark,
The Heretic’s Mark,
The Rebel’s Mark, and
The Sinner’s Mark. Note that
The Sinner's Mark is unfortunately pubbed in April 2023, but luckily all six are on sale at Kobo UK as well...and discountable too!
Here are links:
Kindle UK series page:
https://www.amazon.co.uk/dp/B09DG4K9FG
Kobo UK series page for books 1 - 5:
https://www.kobo.com/gb/en/series/the-jackdaw-mysteries
Kobo UK page for
The Sinner's Mark, which isn't linked to the series page (at least as of now):
https://www.kobo.com/gb/en/ebook/the-sinner-s-mark-3