Cato Institute - "Individual Liberty, Free Markets, and Peace."  An organization dedicated to promoting libertarian ideas, publishing relevant works, and lobbying for smaller government in Washington.

Galilean Library - A free, online resource for those interested in philosophy, featuring articles, essays, forums, and more.

Ludwig von Mises Institute - "Advancing the scholarship of liberty in the tradition of the Austrian School."  An organization dedicated to promoting and discussing the ideas of one of the founders of Austrian Economics, Ludwig von Mises.

Project Gutenberg - A collection of over 30,000 free ebooks, including many classics.  Highly recommended for the impoverished student.

Reason Magazine - "Free Minds and Free Markets."  In its own words, Reason "covers politics, culture, and ideas through a provocative mix of news, analysis, commentary, and reviews. [...] making a principled case for liberty and individual choice in all areas of human activity."

r/libertarian - A very large and active community of libertarians on Reddit.  Well worth visiting on a regular basis.