That's your whole question? Kind of short on details, don't you think? Where do you expect to live - in an apartment overlooking the park on the Upper West Side or in a refrigerator box in Staten Island? Somewhere in between? There ARE five boroughs you know. Manhattan, Brooklyn, Queens, the Bronx and Staten Island. The latter is probably the cheapest and the first the most expensive. Cost also depends on if you want to have a car and expect to pay a lot to park it, if you are going to live alone or with a partner / roommate who shares rent and your general life style.
The next time you ask a question here, provide as many details as possible. Read the guidelines for asking questions too. It won't kill you.