How much is the iPhone 4S bills per month?

this depends on the carrier you will be using.

the talking and texting part is about the same on att and Verizon (~$50). what will vary is the Data. this will be different from carrier to carrier depending on how much you wish to pay for.

sprint has their Unlimited everything plan for $70 a month i believe. an iphone 4S will work with sprint in this plan.

please keep in mind that the iphone 4s is not a 4g phone on ANY carrier