Get rid of your iphone and get a dumb flip phone. Instead of paying for data, you will just pay for calls and texts.
But what about all the apps? Some of them are useful. Get an ipod touch and only use it on wifi. That means you can probably use it at home or at work. Isn't that enough?
How much will you save? I think the data for my iphone is around $40/month, so the break even point for a $200 ipod touch is 5 months.
Probably the reason you would actually do this is if you feel addicted to your phone and you want to help discipline yourself to not need apps all the time, to train yourself to wait until you get home.
It certainly is less convenient, and convenience is worth paying for, and yet discipline is also worth paying for.