Free for now. For now, we're thinking of a $1-2 / stat / month price point with free first 5 stat/months.
Still a lot of discovery to do before we get a clear pricing. Not a priority RIGHT NOW, will become one rapidly.
We're free because we're in beta. Won't stay free. It's a promess. We may open source the whole thing though. Not contradictory at all.
Glad you liked the demo! :)