I've actually been looking at the costs of living in New York. 50k gross will leave you somewhere in the range of 38k after taxes (federal, state, city, and social security). Say you're renting a two bedroom; that's going to be in the range of 24k a year. So you're left with 14k a year. That's a pretty thin margin. At that rate, each child will cut the tax bill by about two thousand dollars, but they're not going to be a net savings -- kids eat more than two thousand dollars of food a year, and they'll also want things like clothing and toys and so on.

75k in New York City proper is about as low as you can afford to support three kids on. And this is assuming public schools, and going to goodwill for clothes.

Now, if you want to know where the blue collar support staff live if that's true has a couple of answers. If you're making under 40k year, there is low income housing available. A lot of them live in the suburbs, or with their parents, or whatever -- it's possible to live outside of New York, and work in New York. And there are a fair number of blue collar jobs that pay better than 75k; building superintendents tend to make more than that, as do a fair percentage of city employees, and a fair percentage of people who own and operate small businesses like bodegas and restaurants and so on.

Rents have come down quite a bit from last year, say. But New York is a genuinely that expensive a place to live.