How much money do I need for an iPhone 4s?

So I want to get an iPhone but my mom says if I get one I need to be able to afford the phone itself and the monthly fees. As it stands right now, I have 400 something dollars. I make 20 dollars a week babysitting but after next week when I'm officially done with school I will probably make about 60 dollars a week. Verizon is my phone carrier so if anybody knows about verizon and what they charge, then you could really help me out.

An iphone 4s with a 2 year contract is $99.99 & monthly data fees can vary depending on what kind of plan you have.ask what kind of plan you have then look on the verizon website for the cost. But if you want to pay the extra $100 i would highly recommend the iphone 5. I'm absolutely in love with mine. The iphone 4s is also very vulnerable to the glass shattering which can be expensive to fix. The iphone 5 also has 4g & LTE which is a hell of a lot faster than the regular 3G that iphone 4s's have.well good luck with your iphone!