We give our kids (12 and 10) $20 a week.

$5 goes to a "family tax" that gets saved up and we jointly decide what to do with every so often.

$5 goes to their personal savings.

$5 they have to donate in the church collection.

And the remaining $5 they get to keep and do whatever they want with.

We have a weekly chore chart they are supposed to complete (with varying results) but mostly like setting them up with the core concepts of (1) you are being paid for your labor and (2) you're only ever going to see a fraction of your paycheck in your pocket.