Where does it all go?

I know a lot of people who don't think it's fair that they have to pay school taxes when they don't have children. What I have a problem with is that even though school taxes are spread out amongst the entire populace, parents are still being asked to pay additional fees so their kids can participate in various school activities. How is it that most people agree that teachers are still one of the most under-paid occupations, yet when teachers try to get more money, the school boards cry foul and worse - parents threaten that they should not go on strike?