Currently $1.99: The Murder of Roger Ackroyd, by Agatha Christie. Anansi Boys, by Neil Gaiman.
Currently $1.99: An American Tragedy, by Theodore Dreiser. 2010: Odyssey Two, by Arthur C. Clarke. A Passage to India, by E.M. Forester.
Currently $2.99: The Cruelest Month, by Louise Penny. Berlin Diary, by William L. Shirer. Edward III: The Perfect King, by Ian Mortimer. The First World War: A Complete History, by Martin Gilbert.
Currently $1.99: Grant Takes Command, by Bruce Catton. Jonathan Strange and Mr. Norrell, by Susanna Clarke. Dirk Gently's Detective Agency & The Long Dark Tea-Time of the Soul (one volume), by Douglas Adams. The Body in the Library, by Agatha Christie. Want to read Christie in French? They have several French editions of her novels, including Murder on the Orient Express and The Murder of Roger Ackroyd, for sale at $1.99 each.
Currently $2.99: Still Life and A Fatal Grace, by Louise Penny (the first two books in her Inspector Gamache series). N or M? by Agatha Christie. Bare Bones, by Kathy Reichs.
Currently $0.99: A Lady in the Smoke, by Karen Odden. The Knight in History, by Frances Gies.
Currently $2.99: Empty Mansions, by Bill Dedman and Paul Newell. The James Herriot omnibus.
Currently $3.00: The Big Sleep, by Raymond Chandler.
Currently $1.99: The Murder of Roger Aykroyd, by Agatha Christie. (A stone-cold classic, and an early Poirot.) And Brunelleschi's Dome: How a Renaissance Genius Reinvented Architecture, by Ross King.
There are also a number of Star Trek novels on sale, but I haven't read the ones I saw, so can't advise to how good or bad they might be. There's also some Kurt Vonnegut.