Nancy Bilyeau’s three Genevieve Planché historical mysteries, two older and one not-yet-out, are all on sale for $0.99/£0.99 right now in the US/UK. The email I got from Joffe books with the sale info indicates the prices will be good for this week only…
The Blue, #1
Buy at Kindle US | Kindle UK
The Fugitive Colours, #2
Buy at Kindle US | Kindle UK
The Versailles Formula, pre-order (coming on 17 April, 2025)
Buy at Kindle US | Kindle UK
Please note, however, that there were earlier versions of both The Blue and The Fugitive Colours, from a different publisher, Endeavour, who went out of business a while back. And those versions went on sale fairly often. So check your library carefully before you buy!