Good day, duckdrop7. I'm here to assist you in importing the existing inventory to QuickBooks Online.
When importing items into your book, there are fields that you can enter, and one of them is the Purchase Cost. We'll have to report the cost of the items since you're planning to process sales soon.
You can follow these steps doing the process:
Then, here's are the articles that you can refer to get more details related to your concern.
Please leave a comment below if you have more questions to ask after you import inventory in QuickBooks Online. Otherwise, you can enjoy the rest of your day. Take care!