Looking for a cheap place to stay for 3 months. (rent, house)

[Playstation4Evr]

Possibly going out to Los Angeles, Santa Monica or NYC(manhattan/newyork,newyork) for a few months next year for an internship, but they aren't paying for housing, where could I find a cheap non-ghetto rundown place for a 19 yr old living off of 500-750 bucks a week? *i know the rent goes monthly btw.. honestly I prefer NYC since it's closer to home but, whatever is cheapest..

[Southern man]

You could go up to the New Jersey shore and pretend your house got destroyed in the tropical storm. You may get a FEMA trailer or some type of shelter.