Best cheap eats
I'd second those suggestions, and also suggest checking out cheapassfood.com or sites/blogs of its kind for affordable places high on quality mostly reviewed by students and people who search for cheap eats. Also, try this thread from CH on $10 and under meals: http://www.chowhound.com/topics/390555
You might also consider going to areas high in volume for cheap eat type places and hitting a few spots in one go around-Chinatown (I also suggest the Brooklyn Chinatown on 8th Ave if you're up for the subway ride) or the East Village. Among a few specifics I can vouch for are Nyonya (Malaysian with spots in Manhattan and Brooklyn Chinatown), Tsampa (Tibetan in East Village), and Island Burger(9th and 51st with great burgers, chicken sandwiches, and shakes).