Buying an iPhone from Craigslist?

Ok, well I have a couple questions. I'm NEW to AT&T & I'm buying an iPhone 4 from someone on Craigslist. 1) Do I HAVE to be in a contact if I buy the phone from them? 2) I'm planning to put it on H2O. A prepaid service for AT&T GSM phones, am I allowed to do that or do I need to be in a contract? 3) What do I look for when purchasing this iPhone from them? How do I know if it's a scam or stolen? I'm planning on meeting up at an AT&T store near me.

New or refurbished iPhone 4s?

I want to get the iPhone 4s and the refurbished phones are $50 cheaper. I was just wondering what exactly refurbished means and if that will affect the quality of the phone. What would you do?

Is it okay to want/have an iPhone at age 16?

I've never had a phone that is mine, apart from the outdated $20 phone my dad gave to me to share with my sister and mom on occasions. I would like a better phone that is my own (not to sound selfish, I hope that makes sense) so I have talked to my dad about getting an iPhone. At first, he said we should keep looking for better plans for the phone. Later on, he said that I don't need an iPhone at my age. I'm not demanding one, I just want a phone that I really like. I'm trying to get a job so I can pay for it myself. What do you think about the whole situation? Are there any compromises my dad and I can make? Any suggestions for good plans in Canada are greatly appreciated.

Problem with Phone Calls on my iPhone

When I make a phone call on my iPhone 4 I can hear the person I'm calling but they can't hear me, it has happened when I tried to call two different people.

I was wondering if this was something I should ask my service provider about or Apple?

My iPhone is ruined. Can I get my info back?

Dropped it in the ocean. Genius, I know.
Anyway, it's still drying out, so there's still hope. But if it is a goner, can I get my photos and things? I have "lost or stolen" insurance, so fixing the phone isn't an issue. It's getting my memories back.

IPhone 4, Touchscreen Unresponsive?

Okay so first off,
>>My lock button is broken. I have been dealing with this using the iPhone "assistive touch feature" which allows me to lock the screen without the button.
>> But now my touchscreen is unresponsive. After doing some research, the best possible solution is just to turn off the phone. But since I don't have a lockbutton I can't do this.

Any tips! Can I turn off my iPhone without the lockbutton? Or how to get my touchscreen responsive again?

Added (1). No, I did not get a new case. )