Here's how to add the cost of the product to an existing product on the Oze app.
Step 1: Search for the existing product in the Products section and click on the desired product (or follow this link for a guide on how to search for existing products)
Step 2: On the bottom of the page click 'Edit Product'.
Step 3: Click in the Cost Price box to start entering your cost price.
Step 4: Click 'Save Changes' at the bottom of the screen.