I am signing up for an online (video-based course) there is one price if paid in full and another is paid in installments. Is there a ribis issue here? Thank you very much
There is a potential ribbis issue here, because you are paying extra due to the fact that the payment is later. You may however pay in full without a problem. Practically though, if the person giving the course is not Jewish, (as is most probably the case, since most people in the U.S. are non- Jews) there is no problem giving him ribbis, and it would be permitted.