There are a variety of websites that are considered the best in free online classes, according to How to Geek. One popular option is MIT OpenCourseWare, which offers lecture notes and exams designed by MIT faculty. There is no registration or fee required for MIT OpenCourseWare, as of January 2015.
EdX is another option listed as one of the best in free online classes. EdX is a partnership between MIT and Harvard, and it consists of free online courses from both universities, states How to Geek. Other websites listed by How to Geek include Open Yale Courses, The Open University, University of the People and Advance Learning Systems Online.