The Accursed, the final novel of Joyce Carol Oates' Gothic Quintet to be published, is $0.99 at
Amazon US and possibly other retailers right now. It's a period horror novel set in early 19th century Princeton. Personally I liked it a bit less than the others in the Gothic series, but it's certainly worth 99 cents. I picked up a Kindle copy even though I already have an ARC of the print edition.