I'd like to add a +1 for Whistle.
Yeah, you get 20-second commercials... Whatev. I used it today when I couldn't figure out why my [cable-based] home telephone wasn't working. The cell phone needed charging and the land line wasn't working. I used Whistle to call the cable company (to find out they were having trouble). No muss, no fuss - just worked.
I like that I was able to sign up and pick my own telephone number. So, natch, I picked one with an area code that the majority of my family uses. Very nice.
Very handy product. And FREE!
Marilyn