How much is a car? 🙂 The question about how much it cost is impossible to answer without knowing what is required. It can be fairly inexpensive but it can also be quite expensive. There is a software portion that includes the licenses to Microsoft and for potential add-ons, and there is a consulting portion that includes tasks like training, configuration, data migration and development. There is also typically a large amount of work you internal people have to put into the implementation. Contact a partner to do an analysis and estimate if you want to know how much it would cost for your business to implement Dynamics NAV and what the return on investment would be.