Have them sort change, and eventually to count it. It teaches them to gather things that are alike, it's an introduction to money and it occupies them for 15 minutes! Just make sure they're old enough to be past the point of putting coins in their mouth.
***Manners!! *** Etiquette is the secret sauce. Everyone appreciates being treated with respect. Etiquette is the art and science of respecting others. It’s timeless and universal. Customs change, hence the need for constant study, but respect is always the foundation. In summary: Be nice. Start with yourself. Study etiquette. It will help you in every single interaction you have, social, professional, financial, everything. Manners apply to every human, in every interaction, even on the hard days. Hence, the need for practice.
Check out from the library or Amazon: “My First Money Book: A Guide for Parents and Children to Saving, Spending, Sharing, and Investing Your Money” by Reggie Nelson
I once asked my mom if my grandmother (her mother in law) was rich. Her reply: “No, but she likes to think she is.” I think she meant my grandmother spent money like she had plenty of it when she really did not. Can relate. I hope you do better!
Work on developing a “no shortcuts” mode. Looking for a faster/easier/bare-minimum option isn’t always bad. People get paid a lot of money for creating efficacy. But there are times when that approach is wrong. Anything you want to grow from (relationships, school, work, wealth, health, knowledge, etc.) those things deserve your full effort, focus and dedication. Play. Definitely play! But don’t f*ck around.
Start saving money early. Save as much as you can.
There are plenty of things worth spending your money on, but be mindful about your money - Don’t p*ss it away.