I haven’t actually implemented this, but I met a super mom who did this…
She would give her daughter $2 a week as an allowance. She would have her daughter give 10% to church, 10% to a charity (and at the end of the year she would write a check for the full amount), 10% for savings, 10% toward the “family home” and then she would have the rest to buy snack at school. If the child chose to spend it all in one day, nothing more would come until the following week. The child had a really good understanding how money worked!
Hopefully this will work or give you an idea!