Red Hat is funding the free plan right now. One of the reasons we started the service this way was so that we would really understand cost control in the public cloud from the point of view of customers. That lead us down the multi-tenancy path (lots of workloads on a single VM). SELinux and Linux Control Groups (as well as a lot of other tech) have been key for us in keeping costs under control.

Check out the OpenShift Origin work (https://github.com/openshift/crankcase) if you are interested in the code that we use to run all of this.