Buying used iPhones on eBay or Craigslist can save a lot of money. The only problem is that some sellers may not be telling the whole story. Apple has taken steps to improve security on iOS devices, including something called Activation Lock to help prevent theft. Protect yourself from buying a useless, stolen iPhone by taking a few moments to check that everything is in order.
The easiest way to determine if an iPhone has been prepared for sale by its previous owner is to see if the device has an Activation Lock. This only happens when a user has signed into Find My iPhone, which means it cannot be used by anyone else. The first thing to do is ask the seller for the serial number or IMEI number on the used iPhone.
Once you have the IMEI or serial number, navigate to Apple's Check Activation Lock Status page. Enter the information in the correct field, enter the code in the image, then click Continue. If Activation Lock is off the device is ready to buy. If Activation Lock is switched on, the page will explain this and deliver next steps to solve the issue.Ultimately, if the owner is selling the device in good faith, they should follow the steps to prepare the iPhone for sale once they are informed of the problem. If the seller is unwilling to turn off Find My iPhone or erase the device completely, then you should not purchase the iPhone. Chances are they don't have the Apple ID required to control the used iPhone, and the device is stolen. Even if it's not stolen, it will be useless to the next owner unless Activation Lock is off.