“Too good to be true” items and quality

Level 4
Sometimes I see deals that look really good, but don’t know how to authenticate if the item is legitimate or faulty. I wouldn’t want to waste my time meeting up and being disappointed, as I run a tight schedule. What’s the best way to know I’m buying what I’m searching for and not sacrificing quality in any way?
One thing is to look and to talk to a seller, but by any chance could there be a certain identifier? Maybe a receipt checker, or bank statement cropped picture, or serial number, imei input, something ??
Level 9
You mention imei, is this thread phone specific?

Ask the user what carrier it was on and tell them to meet you there to double check that the phone is clean (if it has been blacklisted due to being stolen or balance due)

You may loose out on a deal if the seller does not want to do this, but it's the best way.

"Hello there, would you be willing to meet me at the carrier to put my mind at ease that it is clean. We are strangers after all, nothing against you personally."

They say it's already unlocked?

An ESN or IMEI should be provided, once you call in *#06# on your dialpad, give it a try.

While not as accurate, in person there are other ways like stolenphonechecker or swappa, but this assumes the user will let you test the phone for a couple minutes.

Links aren't allowed, but I'm sure you can figure out where to input the IMEI / ESN

iPhone and Android will hace specific sites to check status.
Level 4
I’ve never heard of those apps before. Thanks for the heads up!

Well, I would ask the seller if they have any papers to show that the items is theirs. Also if it is an item that you can go to a store that sells them. Then we would say you should go to that store and ask the staff to tell you if it is real and not fake or stolen. That would be our best recommendation to make sure that you don't get scam.  Also for clothing if the price is too good to be true even if the closes were used then it is better to just look for another seller. We hope this has helped you and that this makes you feel safer selling on offerup.

Level 1
Get a serial number. Don’t buy unless there is a picture of the serial number. And ask the person to write the current days date next to the picture to make sure they are posting it that day and that the picture is real and not stolen from a random photo online.