Let me pay $30 for 1 gig over a year, and I'd do it. To have to use it up in 30 days makes it worthless. I just want it thete if I need it for something while I'm out, not to use regularly.
Unless you spend a lot of time waiting in lines at airports, or sitting on long bus / train rides, or you need it for business reasons, I don't understand how people justify their $70 a month phone bills just so they can watch youtube in their car at a stoplight. If I leave the house I generally have a place to go and something to do there, so unless there is substantial downtime along the way, I don't have time to play with a phone anyway.