<p>This has been discussed (debated?) in other parts of these boards, but let me summarize.</p>
<p>There are several kinds of grad student support available. In the sciences, it is common to receive support from institutional funds in the form of a teaching assistantship, usually for a limited number of quarters. It is also common to receive support in the form of research assistantships, from federal grant funds. Some places have also received NIH or NSF training grants to cover additional support. Usually, in the sciences, support will continue until completion of the degree.</p>
<p>Most of these forms of support come with tuition payments or waivers and a living stipend. The latter will allow a very modest lifestyle. But, since everyone else is in the same boat, it's not so bad. I do not recall if they cover health insurance. </p>
<p>In the social sciences and humanities, support is less common. Where it exists, it will frequently be for a limited amount of time. I understand, but have no direct knowledge, that support in the humanities is more common at top schools.</p>
<p>I do know that some programs will offer support to the top students that they want to attract, and admit others to fend for themselves. Other programs limit admissions to the number they can support.</p>
<p>BTW, some schools require several quarters as a TA as part of the Ph.D. The work is not too difficult, unless you have a big final to grade like I did - 8 pages of short essays (2 questions per page) for 300 students. I learned to read lousy handwriting fast. I also observed that quantity did not substitute for quality. It was very clear from the beginning when a kid did not know the answer and was just going to write a lot in hopes of hitting the answer somewhere. It did not work.</p>