IPhone 4 upgrade AT&T 99cents?

I currently have a blackberry bold with unlimited texting, and the 200mb data feature. My 2yr contract is up so I get an iPhone 4 discounted for 99 cents with a 2yr agreement. I was wondering if upgrading to the iPhone 4 if it will change my monthly bill and make it higher? Or will it be the Same bill my blackberry was.

You have a smartphone plan. Since the Blackberry and the iPhone are both smartphones, you won't need a new plan.

It shouldn't change but with an iPhone you will need a lot more that 200MB per month. I would recommend at least a GB

Just go to verizon. You can get an iphone 4 for 99 cents cheaper