Some singletons, all £0.99 unless otherwise indicated...
A Room Full of Bones, #4 in the Ruth Galloway series by Elly Griffiths:
https://www.amazon.co.uk/Room-Full-B...dp/B006PI6EBK/
The Legacy, #1 in the Children's House series by Yrsa Sigurdardottir:
https://www.amazon.co.uk/gp/product/B01KTS4XRS/
The Silver Pigs, #1 in the Falco series by Lindsey Davis:
https://www.amazon.co.uk/Silver-Pigs...dp/B004NBZFT8/
Closed Casket, by Sophie Hannah, #2 in the estate-authorized continuation of Agatha Christie's Hercule Poirot series:
https://www.amazon.co.uk/gp/product/B01BJ12PEM/
A is for Alibi. #1 (obviously) in the Kinsey Millhone series by Sue Grafton:
https://www.amazon.co.uk/Alibi-Kinse...dp/B004P1JF2E/
The Snack Thief, #3 in the Inspector Montalbano series by Andrea Camilleri:
https://www.amazon.co.uk/Snack-Thief...dp/B004GKMHKG/