According to the Declaration of the International Federation of Accountants (IFAC, 1998), in the management accounting evolution the period after 1995 is characterized by the interest in creating or producing value through efficacious and efficient use of resources using the techniques whuch analyze the value inductors for the customer and shareholders, through institutional innovation. In this context, the concern is to eliminate "non-value added activities", that were characteristic for higher prices without increasing value for the customer. Awareness of this fact was followed by a general mobilization to cover the development of integrative tools and models designed to manage costs and value together, put them in bundles and carry out arbitrage between these two categories of elements: "the stakes is to optimize the enterprise supply by adapting the capital that it invests at the same level that is the customer value of the product". Starting from the definition of value, we intend to begin to explore the concept of customer value and, in particular, we will try to see if it differs from the price paid by the customer. Then we highlight the complexity of the concept of customer, multiple customers and unstable customers, because this is the fact that makes  measuring and ranking the values that they perceive to be difficult, or in any case, relative. In the second part of the article we will look on the problematic relationship between cost and value. To do this we will analyze the main management accounting methods proposed to build this relationship, especially insisting on the target costing method and activity-based costing method.