In step 4 of the output feed setup, you can add extra data information on the cheapest vendor as a custom attribute. This provides additional information, such as Availability, Price, and Price Difference, to the cheapest vendor for each item in the output.
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To add the attributes with extra data fields, simply enable the toggle option and click on "+ Add filter." Use the filter to select what you want to apply to the attribute "cheapest vendor." For example, you can add the filter "top x cheapest is 1" to see the cheapest vendor for each item.