New York Advice?

Okay, so this coming Friday, {June 5th, 2009} I’m going on a trip to New York for school.

Yay!

Anyway, I wanted to know:
What are some good stores/places to visit in New York, and what are the general prices for food and souvenirs? My limit is $100, preferably not spending it all. Don’t say Broadway, we won’t have enough time or money to see a show. Plus, I am perfectly aware that it is there.

Thanks!

Edit: I hear there are some awesome red stairs there. Anybody know what I am talking about/where they are? I’d like to visit them. Thanks again!