The 120 hour online TEFL course is thorough and quite rigorous so you do feel you have achieved something. HOWEVER..... the online teaching jobs world is a thing to behold. I was offered work following an online interview which I successfully passed, but you need to be aware that most of this is China based and so the hours of the day you need to be active are not sociable and there is no demand for other times if day. Also... some of these companies operate very oddly in terms of payment. Sometimes reviews are given by children who just may not want to be there! This CAN in turn affect pay rates (which are often less than UK minimum wage anyway to start.) Bottom line... know what you are getting into. I’d forget investing in extra courses or units until you see what the job situation is like. AND..... don’t feel you have to buy an English teaching textbook from the get go.... not necessary. This is not a career option really so be careful just how much you spend on it all.....