Please review the following website and read about the steps involved in setting up a token economy using the LRBI Checklist:
http://www.olemiss.k12.in.us/intervention/Token.pdf
Next read the following link about the Poyer Purple Paw tokens and respond to the questions listed at that link. http://www.psychologicalscience.com/bmod/2011/10/poyner-purple-paw-tokens.html
You can post your response either here or on the link above.
Please let me know if you have any questions.
--Dr. M