when i first moved here I was making 35k and I was able to survive with a roommate. Now I make more than that and am able to survive quite comfortably for the most part (still with a roommate technically, but you'd be in the same situation)
food here can be kind of expensive if you eat out a lot; breakfasts can be up to 10, while lunch will tend to be 10-15 and dinner around the same price
once a month you'll need to figure in your transportation, the easiest thing, i've found is just buying a monthly unlimited metro card which unfortunately seems to go up every year. When I moved here it was $84 a month for unlimited bus / train service but now it's $112.
there is a LOT of free shit to do in NYC so you can do a ton of stuff even if you're broke.