In the Amazon.co.uk Spring Sale (ends 22/04/2019):
Rosewater, by Tade Thompsom (Wormwood Trilogy 1) is 99p REPEAT
https://www.amazon.co.uk/Rosewater-W...280755&sr=1-54
Under the Pendulum Sun, by Jeannette Ng is 99p REPEAT
https://www.amazon.co.uk/Under-Pendu...81331&sr=1-335
Dune: The Gateway Collection, by Frank Herbert is 99p REPEAT
https://www.amazon.co.uk/Dune-Gatewa...81260&sr=1-274
Omnibus of Dune, Dune Messiah, Children of Dune, God Emperor of Dune, Heretics of Dune, and Chapter House Dune
The Book of Three, by Lloyd Alexander (Chronicles of Prydain 1) is £1.29
https://www.amazon.co.uk/Book-Three-...81220&sr=1-260
Daughter of the Forest, by Juliet Marillier (Sevenwaters Trilogy 1 - except there's 6 books in the trilogy) is £1.49
https://www.amazon.co.uk/Daughter-Fo...81185&sr=1-246
Oddjobs, by Heide Goody & Iain Grant (Oddjobs 1) is 99p REPEAT
https://www.amazon.co.uk/Oddjobs-Hei...81185&sr=1-245
The Tea Master and the Detective, by Aliette de Bodard is 99p REPEAT
https://www.amazon.co.uk/Tea-Master-...81107&sr=1-203
The Martian Chronicles, by Ray Bradbury is 99p REPEAT
https://www.amazon.co.uk/Martian-Chr...80956&sr=1-155
The Hollow Hills, by Mary Stewart (Arthurian Saga 2) is 99p REPEAT
https://www.amazon.co.uk/Hollow-Hill...80919&sr=1-142
Charmcaster, by Sebastien de Castell (Spellslinger 3)
https://www.amazon.co.uk/Spellslinge...280817&sr=1-93
The Cruel Prince, by Holly Black (Folk of the Air 1) is 98p
https://www.amazon.co.uk/Cruel-Princ...2280636&sr=1-7