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.
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.
Take the family on periodic “spending fasts.”
As an exercise, go a day, a weekend or a week without spending any money. Make due with what you have.
Encourage participation. Tie in spending fasts with holidays, lent or in support of a cause.
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.
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.
Check out the Jesuit Volunteer Corp. A short but deeply meaningful immersion into service, faith in action, selflessness and living on a lot less than you think you need.
Start a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.