Find the answer to your question
It's quite easy to implement this yourself by following these instructions which are specific for the "ItemBadgeWidget":
In the getItem and findItemsByQuery functions in the widget, simply add your affiliate tracking details to the URL. Here is the line of code in the functions that shows what needs to be added:
After constructing the apiURL add the tracking details to it.
apiUrl = apiUrl + "&trackingid=<your tracking id>&trackingpartnercode=<your partner code>&affiliateuserid=<your custom text>";
1. For eBay Partner Network users, your tracking id is your campaign id and your trackingpartnercode is 9.
2. affiliateuserid is applicable only for eBay Partner Network and is optional.
That is all there is to it. The Shopping API calls made by the widget will now return the ViewItem links to eBay with the affiliate details included.
Here is a little more of the surrounding code in the widget showing what needs to be done: