Unfortunately, in EFL, there is not a standard that can be applied to all countries. The best thing to do is to check out the sitution in your chosen countries. For ideas on this, you can see my answer about teaching in Peru of 12 September 2007.
It is often possible to get a job without qualifications but the more qualifications you have the more chance you have of getting a job. More importantly, you will have more chances of getting a job with a reputable school.
You also need to consider your own situation, if you want to teach abroad for one or two years, are you willing to invest money and time to get a qualification? If you are thinking of making a career out of TEFL, you will probably come up with a different answer.