The second and third titles in Trudi Canavan's Traitor Spy series have dropped to $3.99 each at Kindle and Kobo US. Not a great sale price, but at least a couple of bucks off of their "normal" prices.
The Rogue, #2
Kindle US:
https://www.amazon.com/dp/B0047Y16K8
Kobo US:
https://www.kobo.com/us/en/ebook/the-rogue-2
The Traitor Queen, #3
Kindle US:
https://www.amazon.com/dp/B007WUW72K
Kobo US:
https://www.kobo.com/us/en/ebook/the-traitor-queen
I liked the whole series, but I really liked the third one a lot. I also think it would help a bit to have read Canavan's Black Magician series before reading this. Maybe not essential, but help.
Finally, if you travel from time to time, the first title in the Traitor Spy trilogy,
The Ambassador's Mission, is on sale for £0.99, as part of the UK Kindle Monthy Deal. Info in @maddz's post here:
https://www.mobileread.com/forums/sh....php?p=3971204