As with most things in life, if it seems like it is too good to be true, it probably is. The really cheap online TEFL courses do not generally include any practice teaching modules and do not prepare you thoroughly enough to be confident as a new English teacher overseas. Put more simply, they do not usually meet the industry-standard requirements.
These requirements are that students have done a minimum of 100 hours of coursework and over 6 hours of practice teaching with genuine non-native learners of English. There also needs to be a accredited curriculum and an experienced and qualified course tutor who has been externally validated. There should also be a maximum of around 12 soon-to-be teachers studying together in a class at one time. Any more than 12 and the effectiveness of the tuition can be less than optimal.
Without accreditation and validation, the quality of a TEFL course can be in serious doubt, and the value of holding a certificate from such a course is highly questionable to say the least. Many employers know the difference and may not accept certification from a dubious course provider.
One of the most famous and highly regarded TEFL certificates is the CELTA (Certificate of English Language Teaching to Adults) which, despite the name, is perfect for teaching both adults and children. This course must be done in person, typically at a university department in a local city. Every CELTA course tutor is carefully chosen and appraised by Cambridge University and in some Middle Eastern countries the CELTA is still the favoured TEFL certification.
There are more and more online certification options on an almost weekly basis, though some of these do not meet the industry standard requirements mentioned above and therefore may not be a wise investment if you want to teach English abroad for several years or in several different countries. The one that we recommend is the University of Toronto TEFL Online. This course provider more than meets the industry standards and is highly regarded by employers globally.