New York CIty is a burger town, and you can while away many happy (and some not-so-happy) hours sampling the various burgers around town. That's what I've done over the years, and I have found three places that consistently serve up terrific burgers at reasonable prices. They are, in order of taste preference:
Peter Luger burger (only served at lunch, but a real bargain at under $10 base price)
City Hall burger (a huge burger with all the sides you'd want, base price $16)
Dumont Burger (incorrectly described earlier here as fast-food -- for an extra treat try a half size order of their mac and cheese, but don't miss either their full size burger at $12.50 base price, or their equally good mini-burger at 9.50 base price)
If I'm in the mood for a burger and can't get to any of the above, I generally look for an Irish pub. I have found most Irish pubs serve up a decent and creditable burger at a reasonable price.
But do yourself a favor and at least once in your life try each of the three mentioned above. You may or may not agree with my comments, but you won't regret your experiences.