A: Division of gains from trade\! Let's say I have a used car whose true value to me is \$4,000, and you are a used\-car buyer whose true value for this car would be \$7,000\. The total gain from trade would be \$3,000, but the exact price at which we strike the deal determines who gets how much of the gains from trade\. If you offer me a price of \$4,001, then you are offering me \$1 of the gains from trade and trying to keep \$2,999\. But, of course, you can always refuse to trade at a price of \$4,001, in which case the \$3,000 of gains\-from\-trade won't exist to be divided, and the final result is that you have a used car worth \$4,000 to you instead of money worth \$4,001\. Now, if there were no market in used cars\-\-if you were the only seller, and that buyer was the only buyer, and no other buyer would potentially come along later\-\-then this is basically the Ultimatum Game\. It happens any time there's a one\-of\-a\-kind transaction with no other potential buyers or sellers\.
Did you just swap the pronouns here? In the previous sentences the speaker was the seller and the listener was the buyer, but now it sounds like it's the other way around.