Offline classes can be expensive when all the expenses are considered. Items such as books, uniforms, and transportation sum up to huge amounts, which is taxing for most parents.
In Online mode, however, there are no extra expenses other than a good laptop and a good internet connection. This, when compared to offline mode, is way cheaper and pocket friendly.
Therefore, the online mode is a cheaper alternative but at the cost of better student-teacher interaction, competition, social skills, etc.