There are a multitude of online TEFL courses on offer. After 30 years of teaching, I doubt that they can teach me much. But since they are so cheap, I might as well get one. Which of the cheaper ones would you recommend, not in terms of the expertise they impart (except for the CELTA and the Trinity(which are too expensive), most of them are probably pretty useless, but in terms of recognition and the ability to get them notarized in Vietnam.