Other People's Helium
NearSys believes in making near space available to everyone. One reason is that my dissertation indicated that students develop a 3% greater appreciation for science as a hobby activity (like amateur astronomy or rock collecting) after completing a BalloonSat project (you can read my dissertation by clicking here).
You'll find many of the files you'll need to begin a BalloonSat project here. This includes securing the help of NearSys and other near space groups to launch your students' BalloonSats.