Hello! I work on the Firefox OS app store[1] . There are no officially supported Firefox OS devices yet- but you can experiment with the simulator[2]. Additionally, they will soon be able to run on any Android device with Firefox for Android installed. (certain apps work already in our Beta version[3])

Hope that info helps!

[1] https://marketplace.firefox.com/

[2] https://addons.mozilla.org/en-US/firefox/addon/firefox-os-si...

[3] https://play.google.com/store/apps/details?id=org.mozilla.fi...