I thought I’d solved the phone issue two years ago. Not so. (See these posts from 2006: 1, 2)
Short story—the TracPhone I had could not be activated with the new Airtime card I purchased as the SIM is no longer valid. It seems that because the number associated with that SIM got allocated to someone else after expiry, the only solution was to get a new SIM card sent out by the TracPhone people (of course, being on the road and needing a phone now, mailing out a replacement SIM card wasn’t an option!!).
So back to the supermarket to buy ANOTHER phone. It activated very quickly, so now I have a phone. But it’s a pain in the proverbial, this whole phone business.
I believe that my new-ish Australian mobile phone will work in the US, but last I checked it costs about $5 PER CONNECTION (plus international timed call charges) to take or make a call on my Aussie mobile in the US. A US$59.99 phone is cheaper! Though I hate the idea of having to throw the old one away.
Bloody phones… Bloody disposable society.
Rhonda Bracey: At Random 
I use my Aussie mobile phone, and have bought a T-Mobile SIM card when I travel to the US. Sim Card and phone num is $USD35 (including some dollars of calls), if I load it up with $100, then I get to keep the number for a year. If I know I’m coming back to the US within a year, I’ll do that, otherwise I might load it up with less dollars. Easy to buy the dollars to load it up at supermarkets; I have had hassles loading up with a single $100 amount over the phone, due to my Aussie credit card. But once I’ve gone through the painful process once, they have my card on record … as long as I use the same card next time (work/personal 1/personal 2…). I find it much easier than having different handsets, and all my numbers in phone memory are still available to me with the other sim card.
Thanks Kirsty! I’ll try that next time. It seems an easier – and cheaper – option.
Instead of throwing it away at the end of trip, use it as a “tip” and give it to a local whom you found helpful, or play the game of random act of kindness at the airport in the US Residents queue.