My uncle is currently employed at The Habitat for Humanity in Montgomery County, TX, and over the Christmas Break, I was able to talk with him about his job and how Habitat operated.
Habitat does not give away free houses. Houses are built by volunteers, as well as housing applicants, and sold, at cost, to applicants with interest free loans. In order to qualify for a Habitat Home, prospective owners must put in roughly 500 hours of labor on other habitat housing projects, depending on location.
My uncle is employed by Habitat to oversee that the construction of community housing projects are being built to code. His salary is paid for by fund raising from the main office of the Montgomery County Habitat for Humanity.
To date, Habitat has built over 400,000 houses worldwide, and in doing so has sheltered over 1.5 people worldwide.