We have a small audio/video company so we buy electronics (TV's, Speakers, etc). at cost and resell them at retail to our clients. So each project is composed of Products + Services (Labor, consultation). We have always entered the products we buy and resell under Type: "Non-Inventory Part" and put it under "Cost of Goods Sold" under "Expense Account" and the Retail price under "Sales". 

The problem we're seeing is that when I Run a P&L report, we see the total Sales number but the "Cost of Goods Sold" line is blank. So we can't see what we actually made on a project or get an accurate picture of what our P&L has been over time. The report looks like we made 100% profit on every job. And that's certainly not the case.