I have a TracPhone and think it is best to activate it and keep it charged. I am uncertain if carrying one unactivated is a good idea...it seems not to me. We have a low tech Nokia that seems to hold its charge for months (not used of course).
We buy 1 year activation with minutes. The minutes roll over each year and they offer double minutes etc all the time.
We use our phone about 1 minute weekly, so this is not a great deal cost wise, but I do think the multiple vendor coverage is a good thing.
Last fall we had a massive wind/rain storm where many parts of the city were without power for many days (we were without for 4.5 days). None of our neighbors had cell phone coverage at their house but we did. I have no idea who was the carrier that was up but it worked for us with no cares at all.
It seems to me that having a TracPhone activated and charged with the knowledge of how to use the stupid things is a better approach then buying the package and hoping you can activate it and learn it.
BTW, I hate cell phones.
We are ham radio operators with RACES affiliation to our local agencies.