Check out this fake money you can create atwww.festisite.com/money. It's so easy!
These are now what my kids earn as their rewards for doing chores and being good. Then they can come to the Reward Store for their pick of a reward and pay the price. Like a half an hour of playing the XBOX is $1. Having a friend over is $2.
They get one dollar each time they earn 5 magnets. Luke has 5 truck magnets and Riley has 5 car magnets. The magnets live on the fridge and get to be put on a little magnetic board anytime they are good and get put back on the fridge for bad behavior. You get the point. I am definitely not the expert on well behaved kids, but I do know this money is super cute and I have been able to run errands with almost no problems with all 3 kids in tow now. You can work it however you want, but when your kids see their picture on a dollar bill that they get to spend, you can't go wrong.