Maria works three different part-time jobs. She works 15 hours a week as a cashier earning $12 per hour, 10 hours a week as a tutor earning $20 per hour, and 5 hours a week as a dog walker earning $15 per hour. At the end of the month, she spends $600 on rent and $200 on groceries. How much money does Maria have left at the end of the month? Let's think step by step and output the final answer within \boxed{}.
user