Now it is possibile to run a completely free Node.js 4 (LTS) server thanks to the OpenShift application hosting platform.
First of all you need an OpenShift account.
Then it is recommended to install the
rhc OpenShift Client tools (you can follow instruction here accordingly to your platform)
Now you are ready to create the Node.js 4 application following instructions available in my repository nodejs-4-lts-openshift. It is a fork of the official OpenShift nodejs 0.10 repository (thanks to ramr and OpenShift work).
Verify the service
If you followed all the instructions of my repository readme you should be able to see an express web application that serve a simple index and a page that shows your OpenShift platform environment variables.
You should see a page like this on your OpenShift app index (mine is http://node4-h4t0n.rhcloud.com)