Many accent students are confused about the correct pronunciation of the article "a." Why do some people say /ei/? You can pronounce it both ways, either as /ɘ/ or as /ei/. It just depends on how quickly you are speaking and whether you pause before the "a." /ei/ is usually used in slower speech and for special emphasis.
So, there's no right or wrong, but you will hear most people say: /ɘ/.