I'd like to start a discussion on old phones that are still kicking. Preferably cheap. The reasoning is, it's good to buy old electronics and recycle. It's also useful to have a backup phone. And let's be honest plenty of old flagships are more than powerful enoigh.
The Nokia N900 is another goldie, if any nerd comes across one, grab it.
EDIT: The only weak spot of the N900 is the physically weak usb port, so applying a tad more solder to it is recommended. Broke mine off, and I wasn't the only one.
I'm typing this up with a nexus 4 .... You can find them in perfect quality (used) for ditcheap (sub $100 on eBay and cragslist) with brand new ones not much more. Hardware is more than enough for basic functionality all the way up to GPU intensive games.
My Nexus 7 (2012) received an official lollipop update from google so I suspect whatever the next version of Android is Google will release an official update for the nexus 4. If/when they don't expect to be able to flawlessly run at least one to two more versions of android by flashing custom Roms as unlocking the bootloader on a nexus phone takes seconds with any toolkit you pick up off of the XDA Forums.
I've got a couple old flip phones around I can use in an emergency... I can't even remember what they are at this point. Then again, my current phone (ST15i) is fairly old and still works perfectly fine. So there's that I suppose.