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.
Practice “going without.” Talk about how nobody gets what they want all the time. We should learn how to just choose to go without something we want. Get them in on the discussion and pick something every day to do without.
Have a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.
***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.
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.
Set up automatic payments so they are initiated on your end, so that you send out money to the bill/ company you’re paying instead of giving them access to take money out of your account.
IMPORTANT: If you borrow money from someone pay it back as soon as possible. In full. If you borrow an item, return it in excellent condition. I’d say if you borrow a car, return it with a full tank of gas but hopefully by the time you’re driving there won’t be any combustible engines. So return it fully charged!
Don’t have a clue? (Relationships / career / character, etc.) The solutions can be found in books. READ! Novels, biographies, history, religion, humor, politics, finance, sports, and whatever sparks your interests at the moment!) You’ll learn about the world, and you’ll learn about yourself. READ!!!! (or listen!)
It’s fine, great, to be thrifty. But please don’t be cheap. Hard-earned money should neither be squandered or hoarded. Enjoy your success! But save more than you’re comfortable with. It’s like my running coach used to say: Keep going until you feel like you’re gonna poop your pants, then push yourself to do another mile. Point is, it should hurt a little.