Hello there, @boots,
I'd be glad to walk you through pulling up a report to get the sub-total of items on an invoice before the tax is added.
You can pull up the Profit and Loss report that shows your gross profit. The gross profit is the percentage of revenue left over after you account for the cost of goods sold.
If you need to customize report, please check this out: Customize reports in QuickBooks Desktop.
Let me know if there's any other reports you need and I'd be glad to lend a hand.