I agree with the others that said to try T-Mobile first. If you can't find it in a T-Mobile store, try their website.
As for Craigslist, exercise extreme caution. Get the person's name, telephone number, email address and license plate of you can.
Meet in a very well lit, busy place OF YOUR CHOOSING, during DAYLIGHT HOURS. Bring a friend if you can.
Also, try to meet inside a Police Station. This way you are sure to not get mugged or scammed. Of course, let the officer at the front desk know you're meeting a seller off Craigslist, for your safety. They won't mind. Just stay out of the way.
Yes, the inner box comes with dark gray security tape. There's an outer sleeve that you pull off to reveal the inner gray box.
Here are photos of my own box and accessories:
Outer sleeve:
View attachment 48574
Inner gray box with security tape on both sides (see arrows):
View attachment 48575
You should also view some unboxing videos on YouTube to know exactly what to expect from the packaging. If anything is off, DO NOT BUY!
If the security take is broken, inspect the phone with a fine tooth comb. Turn it on, play with it. Pop your Sim card in it and make a call. Any seller that's not a scam artist won't mind a quick call to test if the phone is working.
Make sure all the accessories come in the box: USB cord, charging brick, Sim tray ejection pin (see arrow) and Quick Start Guide/Warranty.
View attachment 48576
Ask the seller before even meeting if they can switch the email address registered to the device to yours for warranty purposes or ask that they call up Google in your presence to have it switched on the spot when you buy. If not, ask for their full name so that you can call up and try to have it switched.
If not, ask for the original receipt so that you have proof of purchase because your going to have to deal directly with LG for any warranty and they require proof of purchase since Google will not honor the warranty because you are not the original purchaser.
If the security tape is intact still open the box and inspect everything carefully as I started above. Do it in the presence of the seller so if something is broken or missing they witnessed it and you can get your money back or if it's a brick painted black or a box of rocks you have the scammer right there in front of you and can get your money back or call the cops.
Be smart. Be safe. And if something seems off, GET OUT & DO NOT BUY!
Good luck.
Sent from my Nexus 4