Quartz reveals them. Here’s one…
First, [former FBI negotiator Christopher] Voss offered a price that was low enough to make the other side peevish, but not so low that they immediately walked away from the table. Then, when they came back with a higher price—instead of going through the usual back and forth of meeting somewhere in the middle—Voss simply said, in the nicest way possible, that theirs was an entirely reasonable price, and he was sorry to be wasting their time, because the truth was that he simply didn’t have enough money to pay what the vehicle was worth.
Then, the sales rep felt bad and went to negotiate Voss’ original offer with his manager. He got it. Check out the link for more.