Holding a Tesol Certification may also prove to be more financially lucrative than not. It varies between nations and businesses, but once I had been in South Korea that my annual salary would have been about 1,300,000 greater (over US$1,000). One of the principal reasons I didn't do the teaching certification was because it would have cost me cash in the start -- it would have turned out to be a sound investment, really making me more cash than it cost if I'd completed a certificate.