title: Existing sales/ordering engine that can be integrated to custom .NET app?
body: <p>There's this custom who wants software to generate quotes from a product catalog, print invoices, nothing too original here.
  But they also want a bunch of custom features and a custom presentation, so buy off-the-shelf won't do.</p>
  
  <p>Do you know any good product that we could integrate in the custom dev instead of reinventing the wheel for the catalog/order/invoice management part of the app ?</p>
  
  <p>This is a .NET project in a Microsoft environment.</p>
  
  <p>Any suggestions / reviews are very welcome.</p>