The way accounting works is you pay for something that is the cost
you sell something that is income and sales tax payable

You do not enter cost at the time of the sale and do not just enter a cost, cost is what you pay.

If you are buying and stocking items […]

Resolution for 'accounting works issue: 'Can I add “cost” of an item under “products and services”, so that I can track profit?' available: Yes.

The accounting works issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the accounting works issue yourself by looking for a resolution described in the article. If it is a complex accounting works issue or you are unable to solve the issue, you may contact us by clicking here or by using other accounting works support options.

For more information about resolving issues related to accounting works in Quickbooks/QBO or to get support for the issue 'Can I add “cost” of an item under “products and services”, so that I can track profit?', click the link below: