There are numerous restrictions on employment by foreign nationals, and some types of visas prohibit it entirely.
Most international students are limited to on-campus employment.
Even if you are able to find work, you will not be able to get a job that pays well enough to cover all your expenses. You may, however, take an on-campus job to help pay the bills. You are limited to 20 hours a week while school is in session, provided that you do not displace a US resident. Full time employment is allowed during vacations if you will be returning to school at the end of the vacation period. You may also need to get authorization from the foreign student advisor.