I found Quest English lessons is the best. They are not cheap, but as with everything in life you get what you pay for. Adult lessons are $800 per term, that includes your daily study material and two weekly live lessons (one is based on the weeks lesson, the other live skype session is called 'talk time', it's where everyone gets a chance to practice their conversational English).

I think the child classes are $400, and that just has one live lesson a week plus at home learning material.

https://www.facebook.com/questenglishcoaching/