Had a long walk out of the bush tonight, and would really like to have been able to let my wife know "Hey, I'm totally screwed, but also totally ok, gonna be home late."

Seems to me the best way to avoid needing to send that sort of message, would be to have the ability!

So...I know there's options, who's using what?
What does it cost?
How is the cost structured?
How dependable is it?
Any other pertinent info is welcome too!