The price of an expensive on-site course is not indicative of quality. Online TESOL courses can be offered for a much lower tuition fee because the need to rent expensive downtown classrooms is eliminated. Furthermore, online education provides great economies of scale because schools have a global reach.
While online courses provide a private tutor to every trainee, quality on-site TESOL courses cannot accept more than 15 students. As TESL Canada and CELTA recognize some online TESOL courses, this method of instruction is the way of the future.