I've ordered a ZTE Open Firefox OS phone.
For £60, I thought "why not?".
My current phone is a (almost) 4 year old HTC Desire and is showing its age. I've been expecting to keep it active for another 6 months at least and might still (we will see how things go) but the minuscule storage (512MB internal) and degrading voice quality (harder to hear calls) is forcing my hand a little.
I don't actually know the specs for this ZTE, but for £60 I can't expect much (but perhaps more than my old HTC). And I definitely like supporting Mozilla, which is why I use Firefox as my web browser I'll report back once I've got it and had a play. It's on its way ...