Well, if there's only one buyer, then it's a negotiation between the seller and the buyer. The seller has to answer the question, "Where is the cut-off point wh

Well, if there's only one buyer, then it's a negotiation between the seller and the buyer. The seller has to answer the question, "Where is the cut-off point where it's no longer in the buyer's economic interest to buy from me," and charge right below that. Of course, in such a situation, new sellers will typically emerge.