How much does the iphone cost monthly?

I really want an iphone. My plan is w/ verizon & I have unlimited texting & 1400 minutes of calling. I have a blackberry right now & I don't have an upgrade anytime soon. I just want to know how much the iphone bill is a month & would it be cheaper to open a new plan so I can get the phone for 100 dollars or what? Help Please!

If I'm correct then Blackberry phones require data plans as do iPhones. So the price between the two phones wouldn't be that different with Verizon or any other contract carrier. And when you open up a new plan and only pay $100 or so, you'll actually pay a lot more for just the phone over the 2 year contract ($200 more or so). This means that the phone is expensive and pretty much costs the same as the unactivated phone in the end. Knowing this, you could buy an unactivated phone (there are reasonably priced refurbished and scratch-and-dent ones) and buy a prepaid sim card from Straight Talk for example and get unlimited talk and unlimited text with 2 GB of data for $45 a month final cost (no fees, no data plan).