The widespread practice of scalping has boosted sites like Craigslist and Facebook Marketplace. While not a “random person” per se,[a] you don’t know if that good you’re buying isn’t stolen. Some scalpers, however, will show you the store receipt to prove it’s a genuine scalp(?), and to allow you to return it if it’s defective.

[a]: They are a person you don’t know, but it’s not like a flea market where you can’t read reviews before handing over the money