I use these reusable coupons for motivation in the classroom. You could sell them in a "class store" or you can give them away in the class for outstanding effort, participation or any other reason you can think of that motivates your students.
This coupon entitled the student to borrow a calculator in my math class or for the day, depending whether you are a self-contained classroom. I was always amazed just how popular these coupons were with my 6th graders!
I had 6th graders and they LOVED the coupons!