I recommend The TEFL Academy!

This course was highly interactive with easy-to-follow study units. But what I really appreciated was the amount of support that was provided throughout the course. The online resources provided, extra tips, and almost 24/7 availability of the lecturers made this experience run much smoother than I expected. They also provide a list of jobs and tips for writing a CV so that when you are finished, you can almost immediately start looking for jobs. The delivery of the certificates was much quicker than I expected, and the marking process never took longer than 5 days.