Buying Used Cellphones | Buy / Sell / Trade | Consumer forum

I would be very careful about buying privately unless you know the seller or someone who can vouch for the seller. In addition to the usual worries about whether the phone works properly, the phone could be locked a carrier, it could stolen or it could still be on contract with some carrier. In such cases it will cost you money, probably more than a new, unlocked phone, to make it a legitimate phone. A used phone could also have been implicated in the commission of a crime so make sure that you have a receipt or other proof of when and how you acquired it.

Even if you've covered all of the above, the battery inside a used phone may not hold a full charge, especially if the phone is more than a year or two old. Make sure that you can buy replacement batteries for that make/model at an acceptable price because eventually you will have to.