re: Kindergartners and Bank Accounts

If you're just trying to teach the concept of saving, why don't you set the interest rate that the "bank" will pay. You don't have to be absurd about it but maybe give him a 10% rate that you deposit in addition to his deposits.

You could also do a "company match" where you match 10% of what he contributes to his savings, similar to a 401k program.

I also liked Russian's idea of buying stocks in companies that he is familiar with and likes.