How it works. I googled "UPS collection scam" This was the first (of many!) results
https://www.thatsnonsense.com/the-ups-delivery-facebook-marketplace-scam-how-it-works/
But what is the scam
you get the cash - check it is all there - go and get the jacket and hand it over - video the whole thing as evidence
You have proof that it has all happened but they don't
so - maybe they claim they never got the jacket? demand a refund from Marketplace??
UPS person is not real??
they turn up with less money - but then you can just refuse to get the jacket - but it does put pressure on you to accept the lower price
Fake money?
dunno - anyone seen this is real life and how it goes down??
I'd imagine that there's a problem with getting the cash to UPS, so they'll need my bank details instead.