Pre-paid service (like TracFone) work just fine for some areas and not at all in others. Their phones are cheap ($25+) and cards available everywhere. Where I live, I can't get TracFone coverage at all, any time, but my sister lives three miles away and has no problem. But it has been reported that since TracFone doesn't own any towers, they buy time on all the other towers, so you may be able to get through via them even if your own doesn't work because your company wants use only through their towers.

If there is no access to tower coverage, nothing will work. I think someone said 30 miles max as the crow flies. And I suspect that hills, etc, may interfere even if closer.

Texting can work great, but not at this point with 911. They were discussing implementing it last November, but don't bet your life on it yet.

Sue