Every teacher I've ever known on a personal level has been overworked and underpaid, and still had to go into their own pockets tl provide things for their class, from what I understand it's common practice at schools now to force costs to the teachers, or have them shunt it to the parents (have student bring X for class!) because we dont already pay for the schools with taxes, lunches, after school programs and electives, uniforms, bake sales, candy drives, etc.
AFAIK teachers are often overworked and/or do extra work outside of the classroom. I doubt they'd want a few extra hours tacked onto their existing schedule.