Hello, a teacher in Hong Kong costs about HK$ 20,000 a month. Mainland China can apply, but first you need PGED (Postgraduate Diploma in Education). If you want to be a teacher in Hong Kong, you must have this certificate. Schools offering PGDE are: University of Hong Kong, Chinese University of Hong Kong, Hong Kong Baptist University and Hong Kong Institute of Education. You can study full-time for one year or on-the-job for two years. The cost of tuition is relatively large, so it is recommended to consider it carefully. The salary of teachers in Shenzhen is not low, and they have a teacher qualification certificate. It is ok to take the exam again.