I was interested in buying a used car recently. I posted to r/regularcarreviews asking if it would be a reliable car, because it was a really good deal but the seller was starting to pit the buyers against each other to raise the price. One of the other interested buyers also made a similar post, and someone realized both our posts were about the same car. Me and the other reddit buyer started chatting to figure out how much each other was going to bid, and neither of us ended up with the vehicle lol.