La Cocina, a tiny Mexican-themed hole in the wall, located on 85th between Broadway and Amsterdam, is perhaps the best value you will find in Manhattan!
Their menu is broad, offering a number of different choices of burritos, tacos, and all the traditional Mexican garb. The portions are mid-sized (you walk away content), and minutes after taking your seat, a bottomless plate of fresh-baked, homemade nacho chips and AMAZING salsa (that is free!) arrives in front of you.
Prices range between $8 and $15 (and few that are higher in range) for entrees and $5 to $10 for appetizers (which are large enough to pass as an entree, in many cases).
The BEST part of La Cocina is their 2 for 1 Frozen Margarita special. They have various flavors, offer salted or unsalted rims, and are dangerously good! (2 turns into 4, very quickly)...
The service *can* be slow (they are a bit understaffed during the summer), but the wait staff is generally friendly (the bar staff is great!).
I highly recommend La Cocina to any New Yorker looking for good food at a great value.