Amazon has over 250 Captivating History titles [Kindle Edition] for free.
Examples Titles:
- American History: A Captivating Guide to the History of the United States of America
- World War 2: A Captivating Guide from Beginning to End
- History of England: A Captivating Guide to English History
- The Dark Ages: A Captivating Guide
- Walt Disney and Salvador Dalí: A Captivating Guide to the Individual Lives of an American Animator and a Spanish Surrealist Painter
Full list starts here and carries on for 29 pages.
First paid title you should see is The French and Indian War, but check the price on the left to make sure a title is still free.