Just get on the phone with Verizon when making the transaction and then you'll know. Last year one of my friends bought a Droid off someone on craigslist for only 250 in mint condition. Of course when seeing the ad we thought it was too good to be true but met up with the guy and we call verizon and activated it right in the parking lot. After activation, dude got his money and good to go. See if the buyer is willing to give you the numbers so you can check for yourself. If not, tell them that your intention is to make sure the phone can be activated before you give them any money and that you want to call VZW right in front of them. If they have a problem with that then, it probably is too goo to be true.