I am a non-native English speaker, teaching English now in Thailand. I was thinking about getting a TEFL certificate...

However, before spending the money for a course, I would be interested to know, whether a TEFL certificate is of any use for me, as I neither have a degree, nor am I a native speaker.

As I understand it, a TEFL certificate is only useful for native speakers, who have any Bachelor's degree (or am I wrong ?)...

Well a TEFL or TESL certificate for a native teacher means that they have had X number of hours on "how to teach English"....the fact that they are native speakers means that they know the language.

Is it useful to you (I am assuming you are Thai)...I would say that having a high TOEFL score would be your best asset. I am not sure what the qualifactions of the Thai teachers I worked with....I think it was a Masters (or leading to Masters) degree in Education specializing in teaching English.

I will tell you one thing though...I think you would learn a lot about teaching English from a TEFL course from a reputable centre. In my experience while teaching in Thailand, I heard VERY LITTLE ENGLISH spoken in the classrooms taught by Thai English teachers. They focused on boring grammar, grammar, grammar. Of course this is the reason why listening/speaking skills of Thai students (and frankly a lot of the Thai teachers) are so poor and why there is a demand for Native speakers. If my TESL course is anything to go by, you would be taught a revolutionary (by Thai standard) way of teaching English.

It is expensive though for a Thai salary