http://popmotion.io/guides/feature-comparison implies that popmotion is a free library, but http://popmotion.io/subscribe says it's $9/month. It also fails to mention the difference between Popmotion and PopmotionPro. Any insight on this?
Basically I was experimenting with funding models and Popmotion Pro was a commercial licence that I tried a subscription model for, and a flat rate for. Neither was picking up any traction so I'm still tinkering. It'll always be free for at least personal and non-profit use but I do need to figure out some kind of funding model.