OpenShift
I found one reasonable option for free hosting of nodejs apps. OpenShift by Red Hat
The free tier includes 3 “gears”, which I think are application containers. OpenShift Online Monthly Plan Comparison
Here’s a tutorial for getting a harp app running in nodejs on openshift. Day 8: Harp.JS–The Modern Static Web Server – OpenShift Blog
They actually support other app types as well, e.g. even WordPress.
Netlify
Yeah. This is probably a better option. Offers site rebuilds on github or bitbucket push events. I’m not sure what the free tier includes, but it definitely includes at least one static app/site.