'The American Dream' by Margaret Bourke-White
JSTOR -- A collection of scholarly, full-text articles on every subject.
SocINDEX -- A full-text sociology database. I typed "affordable health care" and got some good hits, including about the impact on small businesses. For a history of health care policy in America, see this article.
Sociological Abstracts -- Another sociology database that indexes different journals.
EconLit -- A great database for economic issues. Remember to put "United States" in your search.
Pew Research Center -- An American think tank that provides information on issues, attitudes and trends. They've got such great data! Search "poverty" for reports like this or "welfare" for charts like this.
US Department of Health and Human Services -- The official definition of poverty used to determine eligibility for assistance programs. This department also administers the programs we call "welfare." Check out the 2014 report to Congress on welfare.