A friend had their 4S stolen and wants to replace it, would rather not get locked in to a new expensive contract so is looking for a cheaper used handset to replace it. We've been offered an old 4 from a known person, it is still locked and is just the handset and the back has a crack but apart from that it is in decent condition, is £80 a fair price? Obviously the software updates but I'm not sure how long old phones are supported by Apple for full use, is there any reason to avoid it? Also is is capable to do FaceTime calls as this is important? Thanks.