Can I pay monthly with an iPhone on Verizon?

A friend of mine renewed his contract with Verizon and got a new phone. He's going to give me his old iPhone 4. I want to know if I can use it on a monthly plan instead of contract, and if so how much would it cost me? It doesn't matter how many minutes or data I just need unlimited texting.

Added (1). I'm not looking for a "prepaid" plan per se, I'm just not willing to sign a 2 year contract.

No, verizon only allows a limited selection of phones on their prepaid plans, and the iPhone is not one of them.

you have to activate it with a standard verizon plan
these start at $40 for a smartphone, $40 for 300mb data, and this includes unlimited talk & text.