Please help me get School Supplies/Clothes

I really need help to get the necessities for school and also school clothes, roughly coming to about 250-300$. I have my own job, but I don't get many hours because the company is going downhill. The biggest my pay checks are, are roughly 100$ and with those checks I pay my 45$ phone bill and get myself and my cat our necessities coming to about 30$. I'm 17 years old, I like having responsibilities and having an animal to provide for because I can afford it but I cannot afford my school supplies, anything helps, please help me ou