You have no idea what you're talking about. A public garage in a cheap part of SF will run you $200-$300 a month, per space. A small non-luxury one-bedroom is about $3500 a month right now, maybe closer to $4,000. A week of groceries at Trader Joes will set you back about $80 a person, if you're frugal and you know how to cook, and you eat nearly every meal at home, and you like leftovers.

Eating out at a restaurant that isn't a taqueria or in-n-out is about $20-$30 a person at the low end. A drink at a bar will set you back at least $6, and probably more like $12-$15. Getting your one-bedroom apartment cleaned once a month will cost you about $100-$150.

I don't have children, but not-rich friends who do have told me that unless you live in a "good" neighborhood and/or your kid can be bussed long distances, you really have to consider paying for private schools, and that's something like 20k a year, per child.

So one-bedroom, one car of parking (not counting maintenance or the cost of the car), eating out at a modest place once a week: $3500 + $200 + $320 + $120 = $4140/mo. That's frugal. Want a kid? Dramatically more.