Don't know for how long, but right now you can get your hands on the digital edition of Katherine Kurtz's excellent Camber of Culdi, first volume in The Legends of Camber of Culdi trilogy and perfect jump-in point for anyone interested in the Deryni saga, for only 1.99$ here.
Here's the blurb:
A Deryni nobleman seeking justice faces a tyrannical king in the magnificent first book of this acclaimed classic fantasy series. Long before Camber was revered as a saint, he was a Deryni noble, one of the most respected of the magical race whose arcane skills set them apart from ordinary humans in the medieval kingdom of Gwynedd. For nearly a century, Camber’s family has had little choice but to loyally serve the ruling Festils, Deryni usurpers who employed dark magic to wrest the throne from the rightful Haldane liege. Now, the land suffers under the tyranny of King Imre, whose savage oppression of the human population weighs heavily on Camber’s heart—a heart that is shattered when the despot and his evil mistress-sister, Ariella, cause the death of Camber’s beloved son. Once he sought nothing more than a peaceful retirement and an uneventful old age, but the grim demands of justice and vengeance drive Camber far from his family’s estates in search of the last of the Haldane line. This descendant of kings will not be easily persuaded to accept Camber’s unthinkable plan. But with the kingdom in turmoil, the aging mage and the reluctant Haldane heir must confront together the awesome, terrible might of the Festils for the good of all.
You can also download The Bishop's Heir, opening chapter in The Histories of King Kelson, for the same price here.
This is the second trilogy featuring young King Kelson and probably not as good a book to begin one's journey in the Deryni saga. And yet, this series has Katherine Kurtz at the top of her game and is truly amazing. I'm persuaded that you can nevertheless enjoy it, though you would be missing on some nuances for not having read the previous series.