Most big scholarships are given out for high SAT/ACT scores. Look in the scholarships section on this site. Do not waste your time self studying AP tests. Colleges don’t care about that and they won’t give you any money for it (though it’s possible you might get some college credits for it). Look on the websites of the colleges which interest you and see what they say about scholarships. Also try asking your GC for information.
Also you should expand your horizons and be aware that $50K per year is not “very poor”. It is actually about the median: "The U.S. Census Bureau reported in September 2014 that: U.S. real (inflation adjusted) median household income was $51,939 in 2013 versus $51,759 in 2012, "