But when I go to purchase, I notice some "supersize" options . . .
There were two for minutes - not a great deal, they were basically like buying a 60 minute card without double minutes. But there was also an intriguing 365 day option! So here's what I got: 180 minutes, 455 days of service for $76.49 including taxes/fees.
If you figure it by minutes, it sounds pretty bad - $0.425/minute. But I was only paying for minutes with $22 of that, so it's closer to $0.12/minute. More importantly, the service costs just $0.168/day, or $5.11/month. (This is on AT&T's network roaming for free to T-Mobile, incidentally.)
So wait, you say, just 180 minutes for a year and three months of service? Well, days of service are what I run out of; most days I don't use my phone at all (yay Skype/MSN!). I have 325 minutes now. and I can buy more at a reasonable rate. For me, this is a good deal.
Bonus: Emergency alarm at work! Traffic was terrible. If this had been a real emergency we'd totally have been toasting in the stairwells.