http://www.sideprojectbook.com/ This is an ebook I put together where I interviewed 39 entrepreneurs who had built a successful side business without leaving their full time gigs.
The data can be collected from a range of sensors like The Energy Detective or Current Cost. That is the current best selling point.
The rest is vision of what this service can be. And our focus in that regard seems very differente, although only a part of that vision is represented in the current state of the app.
Hopefully we will be back in a couple of months showing a couple of disruptive new features.
I have http://www.invisibleobama.com for sale. I'm sure someone with the right attitude could monetize it well since a similarly named twitter account has over 60K+ followers on twitter (@invisibleobama, which i don't own).
If anyone is interested, comment here and i'll get in touch. I'm not asking much.
The problem is at $50/month+ the service expectations become much more expensive to provide -- even though a dedicated member could get it back into the 30s.
Edit: what I mean is that if price ranges from $30-60 the average cost will be a lot nearer that range that's perceived as upscale gym. Whereas ranging from $0-60 would at least appear to be nearer the ordinary $30/month average. It would entirely depend on usage, obviously.