I Am Legend by Richard Matheson is $0.99 at Amazon: The inspiration for Night of the Living Dead, The Last Man on Earth and a the victim of a terrible Will Smith movie adaptation.
Robert Neville has witnessed the end of the world. The entire population has been obliterated by a vampire virus. Somehow, Neville survived. He must now struggle to make sense of everything that has happened and learn to protect himself against the vampires who hunt him constantly. He must, because perhaps there is nothing else human left.