In the civics course that I teach I try to work in lessons about consumer borrowing and consumer savings. One topic that always comes up in these lessons is the differences between banks and credit unions. Young Free Alberta has a series of three videos, done in the Common Craft style, explaining the differences between credit unions and banks. The videos are clearly designed to encourage students to join credit unions. Despite that bias the videos still do a good job of explaining the fundamental differences between banks and credit unions.
Here are some related items that may be of interest to you:
Kid's Economic Glossary
Saving Money in Plain English
The History of Credit Cards in the United States