Final answer:
The listing described is a 'net listing' which is illegal in Arizona and discouraged in many other states due to potential conflict of interest.
Step-by-step explanation:
The type of listing described in the question, where Broker Steve Bennett can sell a property for any amount over the specified $39,000 and keep the difference as his commission, is known as a net listing. This type of listing is generally discouraged because it creates a potential conflict of interest between the broker's financial incentive and the seller's best interest. While not illegal in all states, it is important to note that some states have specific regulations against net listings due to the potential for fraud or unfair practices. In Arizona, net listings are considered illegal.