I have to purchase each of my products from my manufacturer. I want to store the cost for each product, so I can run reports and get my gross profit. I have not found any site that demonstrates how to do this. It seems like this should be basic for Drupal Commerce. Am I using/searching for the wrong terminology?
Just add a new price field to your product type, call it cost, and populate it at will. That's what I do to track my cost on realmilkcheese.com.