"Free" education?

You know that our education isn't really "free" when you are cleaning up the kids play area and find the following note that was used as they were playing school:
"Dear Parent,
Please can you make some donation for a big math test the donation is for money for field trips. Thank you, Jessica Allen."
Yeah, I think my kids caught on how often and how much their teachers were asking for donations.

(don't worry, I don't blame the teachers one bit. I always donate because I don't want them pulling it from their own small salaries!)