What would you do for your kids to start them off when they start working to help them out when they are older.

I was thinking of doing something for my kids when they start working to help them save for the future. Like tell the to pay me like $20 or something each week and I Match it and invest it over time. I was thinking like 20+ years or more. So any good idea that guys have done for four/with your Kids? What’s a good long term

Investment like this