http://www.nytimes.com/2008/04/19/business/19money.html doesn't seem to mention anything about SAT or cost of school correlating with income:

Actual research on the subject is scant, and what exists offers conflicting evidence. One often-cited study from 1998, however, concludes that attending a more selective or elite institution does not translate to an economic advantage for students later on, as measured by their reported income. Attending a more elite college does seem to affect the later incomes of poorer students. The study, written by Alan B. Krueger, a professor of economics at Princeton, and Stacy Berg Dale, then a researcher at the Andrew W. Mellon Foundation, concluded that the qualities that students themselves bring to their education may be what matters most.

Are you looking at the actual studies or something?