My kids earn 5% interest per week on their savings. We also have savings accounts with USAA that I setup when they're born that are mostly for gifts of money from their grandparents on birthdays. My oldest has about $1,000 but if he's got $10 in his piggy bank he'll earn $2.00 in a month while his regular savings account might earn $0.20. It's a bit sad but luckily none of them have saved more than about $40-50 at a time before buying something. 1,264% APR means that if they never spent a penny and started with just $10 they would have over $100 in a year.
My two oldest are already reading 10 books to earn a free book at Barnes and Noble, at their current rate they'll go from start to finish in a few weeks.