My old phones screen is broken so i want a new one. I am look ing at one on eBay, it is an unlocked Motorola F3, and i am wondering if i can just insert my old SIM card in there and it will work just fine? or do i have to get a new contract or something?? please please please help me!!!

Here is the link:

http://cgi.ebay.com/NEW-MOTOROLA-F3-UNLOCKED-SLIM-...