iphone 3GS - slight fault, but easy fix! *

iphone 3gs for sale in excellent cosmetic condition with original accessories and a leather case. ive owned the phone since february but it seems to have developed a slight problem. it froze one day and i had to restore it to factory settings. but now its not recognising my sim card. it could just be my sim thats not working but i dont know for sure. i am advised the problem can be fixed easily and at little expense, but im a bit of a techophobe and dont know much about these things. i paid 185 for it off ebay in feb, so once repaired im sure it will still be worth very close to that if resold, or u would have an excellent phone. therefore im looking for 80 - thats more than 100 less than what i paid just a couple months ago. im looking to sell to someone who might be able to repair it, and i will also consider a part exchange for something else, perhaps even another iphone, like a 4 or 4S and i can put cash towards it - a cash sale for this phone would take priority tho. contact: dave