I hate it when people quote the $70/mo. Do you not pay for a regular cell service? If you actually look at the numbers, the pricing is exactly the standard AT&T plans + $30/mo unlimited data plan. (If you can get regular AT&T at a discounted rate, even better!)

I currently have T-Mobile prepaid and average about $10/month. I really want the iPhone, and can easily justify spending $200 for the device, but I don't want to be locked into a 2-year contract paying $70/month (totaling $1680) when my needs are met with a much more modest price.

Could you go prepaid if you got an unlocked one? I have no idea how that works.

Unfortunately the only reason that device is $200 is that they upped the plan price to cover the hardware cost.