Following is what I've gathered so far along with a couple of items where I need more information. Hope this helps. First get seller to call you from his phone dial pad to your number, so both of you have each other’s number Then go to Settings -> General -> About -> Network and check original Network the phone was for Sellers do not like to give IMEI number over email/phone. So, get the IMEI number while meeting and go to following sites http://swappa.com/esn http://checkesnfree.com/ IMEI number with 01 then GSM, MEID with 99 - CDMA If seller has box then make sure, S/N of phone matches on box and phone Go to https://www.icloud.com/activationlock/ and make sure phone is not locked. If yes then proceed ahead with other tests till you reach the step where seller disables Find My Phone. After that, check this step again Now look for water damage. So ports – charging, speakers etc should NOT have any pink/red spots Check screen, and other physical features Now if you have a sim that you can use on this phone then put it on. Make calls, check speaker, headset, on/off button, volume button, mute button, Check home button Check charging from power outlet Voice recording Go on internet and see if everything works If pubic wifi available, go on a network to make sure wifi is working Take pictures – front and back cameras Ask seller to disable Find my phone if not already done so Ask seller to reset to factory settings Ask seller to remove phone from iCloud Ask seller to send you email or text from his cell confirming that seller has sold phone with IMEI number to you Call Apple Support 1-800-275-2273 and set up phone in your name Following are still some questions that I have How to ensure it is carrier unlocked? How to ensure that it is not under a contract with another carrier? Are there other steps/questions that you'd like to add to the above list?