What are the difference between the two? Which is better? Which is cheaper?
Thanks 
This first level information is available on each school’s web site. Look there.
More specific questions would get you better answers. There are a lot of differences between NYU and USC, chief among these being that NYU is located in New York and USC is in Southern California, with two different climates.
Better – Overall, the schools have similar ‘rankings’ and probably similar reputations overall. East coast, NYU probably better known; West Coast, USC.
Other than that, juliet above has pretty well summed it up.