Duostack (Ruby/Node.js platform) releases docs & info on pricing
blog.duostack.com
blog.duostack.com
Either way, it's nice to be able to create dev / staging / experimental instances which aren't costing 3 cents per hour. I could host these on my own VPS and use Duostack for production only, but I'm more likely to use Heroku for the full stack.
Edit: The first app is free, but my point is still valid.