If a product was delivered directly from an external supplier but the dish is showing as a missing cost price, you will need to add the product to a self managed supplier in order for the dish to update. The price in the dish will not update if you have amended the price in Selling and cost prices. You will need to create the product via Products & Categories and then link it to the supplier. Follow the steps below:
Go to Admin Cogs
icon.Click on Products & Categories
Click on Purchaser Products
Click on Add Product
Enter the details of the product
Once created click into the product
Complete all details
To link to the supplier this can be done form the Buy From tab
Select from the drop-down listing and enter the price