Redwall by Brian Jacques is available for 0.99 at Amazon and BN. This is a classic YA book. I re-read Mossflower ( I think) recently, and was surprised by how much I enjoyed it.
The Claybourne brides by Julie Garwood is available for 0.99 at all the major stores. ( I have read mixed reviews about this one. Some loves the books, some doesn't.)
Dana Marie Bell's amazing Blood of the Maple is discounted to 2.99 at Amazon ( And other stores, but I am lazy.)
A hint of frost by Hailey Edwards is still free at Amazon, BN, and Samhain.