IPHONE WHITE BLACK 3,3GS, 4.4S UNLOCKED ?

WHAT TO DO BEFORE PARTING WITH YOUR HARD EARNED CASH BEFORE BUYINY AN IPHONE. ALWASY ASK BUYER FOR THE SERIAL NUMBER OF THE PHONE, YOU CAN CHECK ITS AGE AND WARRENTY ON THE APPLE WEBSITE. ALWAYS GET THE IMEI NUMBER AND DONT BE SCARED TO CALL THE CARRIER IF NOT UNLOCKED IE ORANGE VODAPHONE O2 ETC, AND ASK THEM IF THE PHONE AS BEEN REPORTED LOST OR STOLEN, IF YOU CALL 3 NETWORK THEY WONT TELL ANY INFORMATION BECAUSE YOU ARE NOT THE OWNER YET. NEVER COLLECT IN A CAR PARK OR ON A STREET CORNER, GO TO THE PERSONS HOUSE AND SIT IN THERE LIVING ROOM, DO YOUR HOME WORK............................GOOD LUCK