I came across some websites which might be useful for people who decide they want a TEFL job without having a lot of supplies:
http://americanenglish.state.gov/?utm_source=EmbassySites&utm_medium=GraphicAd&utm_content=AEHomepage&utm_campaign=AEPromo201212
http://www.grammar-monster.com/
or, if you're planning on a lot of travelling and don't speak English well you could read some of the info....