Don't let the neighborhood, exterior (or even the interior) of this Hell's Kitchen bar scare you away. Rudy's on 9th is the best kind of NYC dive bar.
It's also one of the best places to fill your tummy on the cheap. Get yourself a pitcher of their red beer (also inexpensive) & enjoy free, unlimited, hot dogs with your choice of topping as long as you keep drinking. That could be all night if you have the stamina. Just beware, at peak hours it can get crowded. I like to go for a late lunch during the week. It's never crowded and I can get my fill of beer and hot dogs without ever waiting too long.
Superb people watching also comes on the cheap, it's of course -- complimentary.