Oriental trading has lots of Star themed rewards that aren't too expensive if you have a treasure chest - "Star Studded Behavior"?. I have a clip chart in my class that has 6 different colors. Students start in the middle on green (Ready to Learn). They can move up or down the chart throughout the day, based on their behavior. This was the first year I had used it and it really seemed to be a great tool. It allows students to "make up" for a behavior choice & reevaluate their own behavior. For students who clip all the way to the top, they take home a "happy note". If they clip off of the top of the chart, I will wear their pin on my sleeve. Our principal has even been seeing wearing a few students' clips on his tie It's a big deal.