Reward Money for Kids

We have been working to put into place a system to get our kids to help out with chores and teach them about money.  I have been trying to decide whether to use "fake" money or marbles.  I am deciding to go with the "fake" money route since it will take up less space.  Here is the link for the website "Kids Money Farm" to printing your money.  You can also customize the money as well.