If Salary.com [1] is to be believed (I have no idea), then a summer intern at SPLC makes $95k (presumably on an annualized basis). Lawyer salaries appear to be higher, but still in the low six-figures. Working here would be much less remunerative than working at a firm, but it would have the benefit of qualifying for student loan forgiveness (either through a program that Stanford runs, or through the federal govt's program).
https://www.salary.com/research/company/southern-poverty-law...