Free online help for homework can be found at Slader. It contains additional explanation of topics found in most commonly used school textbooks, and also provides free tutoring online.
On the Slader website, a student can find a listing of subjects and textbooks. After locating the link to his actual textbook, a student can read explanations of problems and questions given in the textbook. Moderated user-provided suggestions and explanations are available for many courses and textbooks.
Additionally, there is online tutoring available if necessary. A student can request a live tutoring session with other Slader users. There are also professional tutors available for a fee.