I have an Oklahoma Tax token and did a little research to see what it was all about. It seems the tax collectors realized there were tiny fractions of tax they were not collecting due to rounding, so they came up with these fractional tokens so they could collect. I believe the tokens were originally issued for certain specific taxes, a school tax in your case, help for the elderly in Oklahoma. There is some information on Wikipedia, and a google search will generate a few other sites. The link below is to the American Tax Token Society website. Lots of info there.
http://taxtoken.org/
Have fun,
Raider