Best Way to do July 4th RIGHT in NYC (Rooftop bars,drink specials)?

So I have a few friends coming into town for the 4th of July and i would like to plan something reallly awesome. Sooo Basically we love to drink and love to drink for cheap. haha. We can start drinking as early as Noon. So my plan that im trying to think up of consists of going into the city and finding places with hopefully some type of drink specials. Maybe something like 2 dollar beers for an hr or unlimited drinks for an hr for like 20 bux. Some type of place where we can drink and drink for cheap and be in the city. THEN im thinking of going to a rooftop bar such as 230 5th for the fireworks and have fun for the rest of the night there. Only problem is I dont really know of too many places offering drink specials and im wondering how early we would need to arrive and what my chances would be to get into a rooftop bar. Soo I know there are some experienced veterans in this who I hope are nice enough to help me out. Pleeaeee any suggesstionsss!!??!? I'll buy the person a drink if the info is helpful.. haha thankssss