Children's Books. There's the classic Aesop's Fables, 365 Bedtime Stories, Children's Bible Stories, and many more. I grew up hearing of these books myself. The stories are beautiful and filled with moral lessons that will help in the development of a child's character.
Character no doubt is important as one grows up into adulthood. So is the subject of money. So why not start reading financial books to your child as early as 3 years old? Surely the effect of that would be interesting.