Any bachelor's degree satisfies many language schools and is frequently enough to qualify for a work visa. Any teaching or tutoring experience even as a volunteer naturally increases one's competitiveness. A business background can also be useful to teach in the many business-English programs. There are a small number of lower paying positions open to English speakers without degrees. However, those ineligible for student or working-holiday visas would likely have to endure the inconvenience of working illegally.
Exchange students are frequently able to pick up a few teaching hours.
If one is considering spending several years abroad or simply wishes to be a better teacher, they are a good investment of time and money. In the period of a few months, they give a basic understanding of the principles of language acquisition, effective teaching methods and lesson planning as well as some practical teaching experience. However, any MA or MEd plus several years teaching experience can sometimes serve as a substitute. Today, the requirement of a Doctorate is becoming more common in the most competitive job markets. Both have their advantages.