Some first-few-in-series specials: $4.99 at Australian / New Zealand retailers, normally $11.99 - $13.99.
Iain M. Banks, Culture (Orbit)
1.
Consider Phlebas
2.
The Player of Games
3.
Use of Weapons
Ann Leckie, Imperial Radch (Orbit)
1.
Ancillary Justice
2.
Ancillary Sword
James S. A. Corey, Expanse (Orbit)
1.
Leviathan Wakes
2.
Caliban's War
3.
Abaddon's Gate
Becky Chambers, Wayfarers (Hodder & Stoughton)
1.
The Long Way to a Small, Angry Planet
2.
A Closed and Common Orbit