Learning English Matters is a great site to get material for teaching English online. They describe the site as an “English learning community & one-stop educational resource for ESL learners and educators.”
They have a lot of digital books, the ones that are used by a lot of Korean and Chinese students. They offer a free and paid plans. For the free plan, you get to access to some of the materials. With the paid plan, you have unlimited access to all materials including the premium books plus support.
Their premium or paid plan costs $15. For this one time payment, you get to download all the books on their site. Not bad!
For more information, visit http://englishmatters4u.com/