Wow, this is a textbook example of seeing an opportunity and grabbing it. From starting with an MVP to AB-testing the prices to increasing your signup rate with a simple change of the CTA button, it's an example many developers should follow. And while it may not be a huge success in your eyes, I'd say it's pretty awesome either way.

Shame this post didn't get much views yet, I hope you keep posting great stuff like this :). Resteemed in the hopes that you may get some more upvotes on it!