Buyer-Seller - This is a great first negotiation exercise. There are two roles and it takes about 10 minutes to negotiate and 15 minutes to discuss the outcomes. While most of our games have up to 8 roles and a possible role for a team leader/mediator, this game has only two roles and it is not appropriately broken into 7 phases or legs of the journey.
If you so desire, you can have each pair of negotiators put their results up on the white/black board - typically these will range from $15-$35 per gallon and whose trucks are going to be used to deliver the T-4 chemical. You might at this point ask why there is a range of outcomes, what seemed to work and not work, and what participants would do differently next time. You can also ask what are the most important elements of a negotiation or skills of a negotiator. Lastly, if time permits, you can ask what the negotiation was about (the business context).