Although I am a student and cannot afford to make any financial donations, I nonetheless strongly support and champion the causes of the following four organisations.

Do Something
http://www.dosomething.org
Do Something encourages and empowers young people to make a difference in their communities and the world around them by asking them what they want to do. The organisation provides resources, training, and financial assistance to help young people launch their own projects for prosocial change. Do Something partners with companies such as MTV and Nike, as well as high-profile celebrities, to motivate young people to become interested in important social issues and to become young leaders in their communities.

Big Brothers and Big Sisters
http://www.bbbsi.org, http://www.bbbsa.org, and http://www.bbsc.ca
Big Brothers and Sisters is one of the oldest volunteer organisations in North America and around the world. Through its mentorship activities, it continually strives to provide positive role models and social support to children who might otherwise have few, if any, people in their lives to help them realise their potential.

Carnegie Corporation of New York
http://www.carnegie.org
The Carnegie Corporation is the grant-making foundation launched in 1911 by U.S. steel magnate Andrew Carnegie, to promote "the advancement and diffusion of knowledge and understanding." Through the operations of his company, Carnegie Steel (today U.S. Steel), Carnegie became one of America's wealthiest men. He steadfastly believed, however, and was one of the first wealthy individuals to publicly declare that the wealthy have a moral obligation to give away any riches above and beyond those needed to support oneself and one's family. Accordingly, in his 30's he started donating to social causes what would eventually become nearly all his money. A strong believer in literacy and education, Carnegie and the Corporation built 2,509 free public libraries throughout the English-speaking world, the goal being to afford everyone a means of self-education. He founded Carnegie Mellon University and the foundation that today helps support both national and international initiatives "to do real and permanent good in this world." The foundation's four main programming areas are education; international peace and security; international development; and democracy.