Zero Dollar Invoice

Summary

We have a business case where the customer has a scenario to send the Give away/Prototype/Demo items to Customers

Content

Business Case : 

There are Give away items for Potential customers and  Prototypes/Demo items that go through the Sales reps to the Customers 

In this situation when a sales or Marketing department requests for an item to Demo or sometimes give away the same to customer , how do we handle this in the system from the transaction perspective and from charging the sales/marketing department 

Also once the item is issued to the sales department the same is shipped to the customer at zero cost