I don't have a UNC buddy, but I have had the chance to talk to some current PhD students in my department, health behavior. Apparently there's scholarships and grants of course, but for everyone else there's three options for funding: full RA/TA, half time RA/TA, and stipend-only RA/TA (these all have official names but I don't know what they are).
Full RA/TA: Work 17-20 hrs/week, tuition covered completely, health insurance covered, "full" stipend which is ~$7500
Half RA/TA: Work around 10 hrs/week, tuition half covered, health insurance fully covered (?), "half" stipend which is ~3500
Stipend-only RA/TA: No tuition covered, stipend depends on hours worked
So obviously this isn't very detailed but it's how two students have explained it to me so far. Compared to other schools (ahem, JHU...) it seems like a pretty good deal to me. Cost of living is definitely lower here than the places some folks on this thread are coming from (Boston, NYC, etc.), but is actually a bit high for NC. Maybe I'm spoiled from growing up in a very low cost area haha. Depending on where you live around here, you don't necessarily need a car because Chapel Hill has a good bus system, but it sure is nice to have. Anyway, I work and live at UNC so I'd be happy to answer any questions folks have about the area.