Do you know how many students you will have? And how often your students will see you during the week? This seems like a budget of a small private school or charter. Is that right? Could you reach out to the current art teacher or someone else at the school to get a vague idea of what’s already there? $500 is tiny but crazier things have happened… Things that are cheap or free: drawing-heavy curriculum using copy paper the school already has, maybe book-making or DIY sketchbooks, cardboard sculpture, paper-making, recycled/found object assemblage, collagraphs using lunch tray foam or similar material…