For sellers: how to spot a scammer.

Level 5
1) They ask you to text a friend or family about an item.
2) They want to communicate outside the app
3) Ask if you will ship the item even though it says local pickup only in the description
4) Frequent misspellings and grammatical errors in their post.
Feel free to add your own.
Level 9
5) In conjunction with the above, they are usually recent account sign ups with no ratings.

A recent sign up does not automatically mean a scammer, just use your own judgement based on how they present themselves.

6) Any mention of certified checks is a scam.

7) In person transactions which require a deposit are a scam half the time.

8) They ask that you meet them late at night at an odd location, usually with no lighting or cameras.

9) "Can I pay you via CashApp or PayPal?" scam.

10) "I am interested in what you are selling. Can you please e-mail me?"
Level 1

They are sending their "movers" to pick up the item.

Level 9
@H8Scammer :
"Buyer insists you bring change for a hundred...
This is a set up the buyer intends to launder a counterfeit hundred dollar bill for your green!"
Level 9
"Friends Abroad" via PayPal appears to be another scam according to @bellavida
Don't forget the ones who do show up & only bring a 1/4th of the asking price. This has happened to me five times now. Didn't work for them either. Nor did begging. Or being pushy. Or the one that tried to fast talk me. $20.00 means $20.00...not $5.00 ;-)
Level 5
Yes indeed. The people who show up and somehow don't have the agreed upon money are annoying. I simply tell them they can either find an atm or have a nice day.