The latest catalogue from The Book People has a couple of great offers:
Three Daisy Dalrymple novels by Carola Dunn for £4.99:
Death at Wentwater Court
The Winter Garden Mystery
Requim for a Mezzo
which are the first three in the series.
Carola Dunn's bibliography is here.
Ten Ian Rankin books for £9.99:
A Question of Blood
The Naming of the Dead
A Good Hanging
Set In Darkness
Ian Rankin's bibliography can be found here.
More multi-titled sets can be found here including the Martin Beck series by Sjowall and Wahloo for £9.99. P & P is free when you spend over £25.