Here is a very good overview of the capabilities of Dynamics NAV 2013 and how to buy it.

Microsoft Dynamics NAV 2013 is a business management solution for small and mid-sized organizations that automates and streamlines business processes. Highly adaptable and rich with features, Microsoft Dynamics NAV enables companies to manage their business, including finance, manufacturing, sales, shipping, project management, services, and more. Companies can easily add functionality that is relevant to any area of operation, and that is customized to support even highly specialized industries.

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