How to best import Downloadable Digital Products into Inventory

How to best import Downloadable Digital Products into Inventory

I have a large number of downloadable digital products that are sold B2B (think PDFs) that I want to track the sales of alongside their physical counterparts in Inventory and be able to send Invoices for these digital products.

These items have no cost price because they are digital.

I am able to manually import an item, but I can't upload via spreadsheet. 
When I try to just upload the first line of the template spreadsheet, I get this error: 

Invalid value passed for Item Code
 
When I try to upload our item, I get this error: 

Enter the cost price of the item.

This is even when I enter it as a service or try putting a field with a price of 0

When googling, I saw a help page that said that digital products should be listed as services. But it's asking for a cost price if I try to list it as a service as wel..