Get three months free!
Each person who joins the site creates a little extra work for me here in the background. (I write the definitions and gapfill exercises -- it should only ask you for them if I'm too slow). So, I can't offer this for free. Not forever.
But, and I can't stress this enough, there will be some difficulties as the system goes from a thing that's great in my classes, to a thing that's great for a lot of people. I'm happy to let you use it for free in that time. In fact, by using it and being communicative, you're helping me out quite a bit.
So, enjoy the free trial and know that I'm looking forward to hearing what I can do better!