I Want to Buy Used Factory Unlocked iphone 4s?

Dear i want to buy used factory unlocked iphone 4s.could you please tell me what kind of things need to check buying time? And how?

If you are looking for factory unlocked IPhone 4s then Apple IPhone 4s will be best smart phone for you. I'm user of this phone since it's launched. I still not facing any problem from this phone. It's online price Rs.- 23,'190/-.
Features:-
1. 5 MP Primary Camera
2. 0.3 MP Secondary Camera
3. 3.5-inch Capacitive Touchscreen
4. HD Recording
5. Wi-Fi Enabled
6. Bluetooth Support
7. 8 GB Internal Memory

http://www.shopbychoice.com/apple-iphone-4-8gb-black/p/TWpjME5UST0

  • Will an unlocked iphone 4S work for tmobile if it isn't factory unlocked? I want to get an iPhone 4S and my friend has the iPhone 4 unlocked but i'm worried that if i get it non-factory unlocked it won't work. My uncle tried to do it a couple of months ago and apple said that if it was factory unlocked every time the phone shut off or died it would reset. I was just wondering if the same thing would happen if it wasn't factory unlocked? So if I get it unlocked everytime it will shut off it will reset? That is what i'm worried about.
  • Where to buy a factory unlocked iphone? Where is a reputable place to buy a factory unlocked iphone (no ebay please).It doesn't have to be the newest model but want a new or maybe used factory unlocked iphone.
  • What to do if I want to purchase a factory unlocked iPhone? Ok so i currently have a boost mobile phone which is pretty crappy, and I was looking on ebay for a factory unlocked phone probably from at&t or t-mobile because i heard that if they are factory unlocked all i have to do is put a new sim card with my desired network and that's it. At least i think so… So i want to know what exactly it is that i have to do to make the iphone work on let's say straight talk or at&t as a prepaid phone? Please need step by step.
  • Unlocked vs factory unlocked iphone? So I'm thinking about getting an iPhone but I wanted to know if I could take an unlocked iPhone to the Verizon store an them set it up for me? I have no clue what the difference between factory unlocked, unlocked, and locked iPhones are