Hi there, PAlcala. 

Welcome to the thread, and thank you for adding a screenshot. I'm here to lend a hand in correcting your average cost.

Changing the cost of an item prior to the created transaction doesn't affect the average cost. That's the reason why it's showing as zero. To get this resolved, you can create an inventory value adjustment. Before doing so, you may consider reaching out to your accountant for guidance in adjusting your inventory. Doing this helps ensure your cost average is calculated correctly.

For steps in creating an inventory value adjustment, check out this article: Adjust your inventory quantity or value in QuickBooks Desktop.

In case you want to make data entry easier and faster, you can use a barcode scanner and barcodes. For more details, see this article: Set up and use barcode scanning in QuickBooks Desktop.

If there's anything else I can help you with, let me know in the comment section. I'll be happy to answer them for you. Have a good day!