Before Buying a second hand phone or camera you must check whether the device is having any fault or something which might make you discomfort.
The possible reason why another person is selling his item at low price must be its not working properly or some feature might be missing.Be alert and enquiry about product and if possible get its details from net also. You Must check price rate at internet and what he is offering you.He might be befooling you.
You should meet the person face to face in order to deal effectively and be safe on your part.Not always 2 nd hand product are gud as otger man might have thought something before selling it. Only tip is to look each part carefully so that you might not waste your money buying useless thing.
Thanku