My wife and three daughters (4 phones) all have iPhones on AT&T go-phone plan with no data. I guess technically there is a "pay as you go" data plan associated with the line, but I have the data functionality turned off on the phone, so no data is used. Wifi is so common now, none of them have really complained about not having data. Costs me about $10 per month for each line.
And if anyone has an iPhone 4 in a drawer that they can't use, send me a PM with a price... #1 daughter needs a new phone.