Does anyone had success selling software hosted on managed platforms?

I am not a devops person and smarter people that me did solve all those issues. Heroku, Google AppEngine, etc... So, are there any people that managed to build a business around PaaS platforms.

• How do you handle pricing? I was thinking about just applying a factor to the AWS bill, does it work?
• Also, is it possible to programmatically cap the spending?
• Does PaaS vendors make it easy to re-sell their services?