need $300 for college expnesed

I am an international college student in the US.. and due to some miscalculation messed up on my college payments. After all the money i get from my shcolarship and money from my parents I am still $250 for books. There are no jobs available on-campus and also it is illegal for me to work off-campus.

I used to earn good money from my tennis lessons but i cannot play now as i just got a surgery done.

If anyone has any ideas just pass it on.. i have sold of my extra books and stuff...