My kid has a savings account. All the money that grandparents send for birthdays and every damn holiday you can think of goes into the account. It's like $250. Nothing ever comes out. We just always buy her what she wants, even when she specifically asks for her own money. Like the other day:
Daughter: Can I have $100 from my account?
Me: What for?
Daughter: Art supplies.
Me: I don't want you spending all your money like that. Here's $60. That should be good.