Byrd scholarship gives out 1500/year for 4 years. Each state has a different nominating and awards process. In Oregon, everyone apply to a statewide scholarship organization run by Oregon Department of Education. Other states have principals nominate 1-2 students. This scholarship is not based on financial need, and I think GPA and SAT/ACT play the biggest part (if not the only part) of the awarding process.
More information can be found: http://www.ed.gov/programs/iduesbyrd/index.html
Selective service is for guys only. I don't know if it's tuition only.