Yes! Parlay is free for any teacher to create one course. Click here to get started with your first course.
Pro tip: You can invite as many students as you want in a single course. When you create a discussion activity (called a RoundTable) you can simply select which students you want to include in the discussion. In practice, you can have all of your classes in one Parlay course, and simply invite the right subset of students each time you want to run a RoundTable.
Hope this helps :)