I bought the 4S 32GB (locked) with a new contract. It came out to ~$360, if I recall correctly.

I'm with Verizon, so monthly payments would be ~$100. But because I like to save money, I'm on a family plan with other people and we divvy up the costs. Because of that, I end up paying way less than the regular Joe. I pay $50/month and I feel I can still pay less, except there is a married couple in the plan, and friends and other relatives, and the costs are divided slightly unevenly. Anyway. I don't know the specifics of the plan, because I hardly use my phone. But I think it goes something like unlimited texts and 1000 minutes shared, and for my line, 2GB of data. 2GB data alone costs $30 with Verizon.