There is a high school around me that has a 18 Disc Golf course set up on its property. It's part of there gym class. I would start there, getting into gym class, then set up a Disc Golf Club.
Tournaments/Leagues could be held for the members. They will be competing between themselves unless you can include some of the other clubs in the area and make it a fund raiser for the club.
If the school won't financially support it, I believe that would be a great way to raise some funds. As you go through the process write down what your doing and how, that way you have a guide to give other PE coaches/Schools in your area to start clubs.
Once enough schools have clubs then the process of setting up a school team can begin. But you got to lay it out how to start for the other schools because there probably won't be any DG'ers in the other school to have the motivation to figure it out themselves.
I do remember one of the online sites sells discs in a lot of 30. 10 "Drivers" 10 Mids 10 Putters. I can't find it at the moment.
On a side note, high school ball golf teams don't play just themselves they play against other competing schools.