[kdmccormick]

Cost would be negligible compared to a teacher's salary.

(1 teacher / 20 students) * ($50k / teacher-yr) = $2500 per student per year to fund teacher salary.

Compare that to $40/yr domain+hosting, which maybe 10% of students will use. $4/student-yr will not be the diffence between paying teachers probably or not.

[lxgr]

That budget only works if you don't care about content moderation or abuse management at all – or did you expect teachers to just do that on the side?