Is There a Grant System to Compensate Therapists?

Many therapists offer reduced rates for students and people who can't afford more. How do they do this? Is there a grant system to compensate therapists? Do they write it off on their tax how does it possibly work that all these professional people who need to earn money can so regularly offer their extremely valuable services for rates that are less than what they are worth? It's a wonderful gift, horse, and i want to look it in its mouth. Peace moose.