To determine whether there is a positive bargaining area, each party must understand its gain or its thought price. For example, Paul sells his car and refuses to sell it for less than $5,000 (his price at worst). Sarah is interested and negotiates with Paul. If she offers him a little more than $5,000, there is a positive bargaining area, if she is not willing to pay more than $4500, there is a negative bargaining area. On the other hand, the buyer wants to pay the lowest amount possible, but he can consider a higher amount that he may be willing to pay. The maximum amount they are willing to pay is also called « booking price » or « departure » from the point of the buyer`s agreement. The search process for this area requires a bit of detective work for it to work. It begins with a proposal from a person, business unit or organization known as a « partisan. » In essence, it is the person who puts an offer on the table. The adoption of a proposal is called a « prospectus. » This is the person or organization that considers the merits of the offer or proposal. The person concerned will accept the proposal, make a counter-proposal/counter-offer or reject it altogether. This is where the game starts to have a lot of fun.
Let`s say, for example, that Dave wants to sell his mountain bike and equipment for $700 to buy new skis and ski equipment. Suzy wants to buy the bike and equipment for 400 dollars and can`t go higher. Dave and Suzy did not reach ZOPA; they are in a negative bargaining area. When both parties know their BATNAs and leave their positions, the parties should be able to communicate, evaluate the proposed agreements and, finally, identify the ZOPA. However, parties often do not know their own BATNA and even less know the BATNA on the other side. Often, the parties can pretend to have a better alternative than they really do, because the right alternatives usually lead to more power in negotiations. This is explained in more detail in the BATN trial. However, the result of such deception could be the obvious absence of ZOPA – and therefore a failure of negotiation when there was actually a ZOPA.
Common uncertainties may also affect the parties` ability to assess potential agreements, as the parties may be unrealistic or pessimistic about the possibility of reaching an agreement or the value of other options.  It is a great advantage to know the upper and lower limits of a ZOPA. It is understandable that a negotiator is reluctant to take a step forward, or ultimately, because it is the least attractive activity they would accept before moving away from the negotiations. If you know the limits of a ZOPA, it is possible to bring your opponent closer to his limits to get an advantageous deal. When you enter into a negotiation, you rarely know the size of the ZOPA or whether there is room for an agreement.