I retired my old Nokia last year after two buttons went bad, the 0 and 9, but I still have the phone. My Samsung now is pretty nice, but it's one of the cheapest models you could buy. I mostly just use it for phone calls.
I still do that. I buy my minutes at a local supermarket, which is enough for about 3 months.
I use to keep my old Nokia in my car for emergencies, like yourself, but I don't do that with my new smartphone, specially to protect it's data from the heat over the summer.

