3 years ago I bought a pair of cheap FRS for exactly this purpose. $20.00 for the pair, with rechargeable batteries and chargers. They were cheap enough that I thought I would use them like SOMA was thinking. I thought they were 'disposable,' but they are still working well. I take one with me, and if My wife needs me to come back in, stop and pick up food, or whatever.
I would not rely on it for emergency use. I'll probably buy a VHF with the FRS capability for long trips, like Catalina.

The radio reaches as far as I can get on my lake, and almost as far as I'm willing to go in Mexico.

They also come in handy to talk between cars on trips. Also good for hunting and camping.