These books are cheap in Kindle form right now.
First, One Day in the Life of Ivan Denisovich: A Novel (FSG Classics). I mention this here simply because it was a book that influenced me as a kid. Made me realize that starvation was a thing.
If you’ve not read The Martian: A Novel, read it. Fun book. This is where science fiction is enhanced significantly but science and math geekiness. Destine to become a classic.
I know a lot of you are fans of forensic fiction. Puruant to that interest, these two books by Patricia Cornwell: Ripper: The Secret Life of Walter Sickert [Kindle in Motion] and Chasing the Ripper (Kindle Single), in which life imitates art.