I have a dog themed classroom, so I decided to remake my mini economy money. I use this as a positive behavior incentive for my students. They get paid for such things like their weekly classroom job, good grades, awards for games, and active listening. I also use this for simple behavior infractions such as talking in the hall ($1 doggie bone fine).
I chose to copy these on to green paper and laminate for classroom use year after year.
These dollars have a realistic look to them with the fun of dog faces. Students will have the life experience of counting, trading in, and spending them in whatever way you choose. I like the idea of a classroom auction with prizes they buy. This mini-economy idea really instills real world math and economics in the classroom.