Several of the early books in Anne McCaffrey's Dragonriders of Pern series are now 99p at Amazon UK
https://www.amazon.co.uk/gp/product/...oreType=ebooks
They are:
1. Dragonflight
2. Dragonquest
3. Dragonsong
4. Dragonsinger
5. The White Dragon
6. Dragondrums
7. Moreta
9. Dragonsdawn
16. The Skies of Pern is also 99p as part of the monthly deal (as posted above).
I don't know how long the other eight books will stay at 99p.