I guess it depends whether you’re an undergraduate or a grad student.
I’m a foreign grad student here in the US, and by the time i pay for rent, utilities, books, food, etc. i definitely need 15 grand, and this doesn’t include much entertainment, or trips away, or research trips and expenses.
As a foreigner applying to grad school, i essentially had to limit my applications, paradoxically enough, to very expensive private universities. Those are generally the only schools with enough money to give their grad students a free ride through most or all of their degree, and i could not have afforded to come here otherwise.
My school currently charges about $28,000 a year in fees. For grad students, this amount generally applies for the first four years of your degree, after which you are considered a “non-resident” candidate and are only charged 10% of this, on the assumption that you spend most of your time off-campus researching and writing your dissertation (almost all grad programs here are PhDs; very few terminal Masters programs).
The university covers my fees for those first four years; after that, i’m responsible for finding the $2,800-a-year non-resident fee, although there are rumours that this fee is going to be reduced or waived very soon. The university also currently covers two thirds of my medical insurance bill.
On top of the fees, we also get four years of funding in the form of a stipend, which is not much, but is pretty much enough to live on for the nine months that make up the school year, September to May. You really need a job over the summer to supplement the stipend, and this is harder for international students, because our visas (usually F1 status) severely restrict the type of paid work we are allowed to do. I’ve been lucky enough to get a couple of good research assistant jobs on campus, which is allowed under the terms of my visa. I could also work in the library, or an admin job on campus.
After the four years of funding runs out, we are essentially on our own, but there are quite a lot of scholarships and fellowships available from foundations, universities, etc. These are very competitive, and often very hard to get, but they exist. Also, some universities, libraries, and archives have available smaller grants to help defray the costs of travel and accommodation for research trips. Again, foreign students are often restricted here, as many fellowships and grants require the applicant to be a US citizen.