Beautiful atlases which are in excellent/mint condition by John Haywood. They are wonderful for learning about geography in the time period you are studying. Hardcover $10 per volume plus shipping.
The Ancient World: Earliest Times to 1 BC Volume 1
Medieval World AD 1 to 1492 Volume 2
The Age of Discovery: 1492 to 1815 Volume 3
Modern Times: 1815 to the Present Volume 4