Others sell you a software tutoring program to learn mathematics. This in reality is not a tutoring personal service. There is also the math tutor that sells a newsletter on mathematics topics. Again consult in the open forums or chat groups. This site is also run and monitored by Swarthmore College and it is part of Dr. Math.
Registration is required.
This site offers a wide range of forums to discuss different aspects of mathematics. Once you submit a question you have to be prepared to wait for an answer from another reader of the site. This is a cite of the Star Tribune that consists of discussions about different areas of mathematics. You need to register. They also offer to answer your questions within 24 hours.