Certell

History and Social Studies curriculum available for free from a non-profit, bipartisan organization. There are currently courses in American History, Government, and Economics, with World History in the works. Courses include e-books with embedded audio and video, plus course files (for planning and assessment) that can be used with a learning management system, Google Classroom, or downloaded for offline use. Looks like a great option for high school level students.

Subject: 

Religious Content: 

None

Price: 

Free