When a consumer purchases an item, the presumption is that the benefit obtained from it exceeds the price paid—we can think of this difference as the consumer profit. How do consumers calculate this profit, especially when they do not immediately consume the purchased item? This technical note presents a model of mental accounting that gives insights into the process that consumers follow to calculate value. It compares rational logic, accounting logic, and mental accounting logic, incorporating the phenomena of loss aversion, transaction utility, and consumer anomalies. This note is used at Darden in the second-year "Behavioral Decision Making" course. It would also be suitable in courses covering rational decision making in business.