My children and students loved the golden bead material. It is base 10 material that you can make or even buy at your local school or educational store.
It’s a wonderful foundation to the decimal system. Most currency is based on the decimal system as well. If you want to use money, use 110 pennies, 10 dimes, and a silver dollar to introduce the decimal system. Just substitute the money for the golden bead or base 10 material. You can introduce a child as young as three to the first golden bead presentation!