Following the announcement to launch seller merchandising items on all fixed price listings, we are now testing this to include Auction-style listings from 17th May. You may begin to see relevant merchandise including merchandise from other sellers on active view item pages during the next couple of weeks.

Cross-merchandising on other sellers’ item pages is optional—you can opt out at any time by changing your settings in My eBay.
 

• Log in to your eBay account.
• Under "Account," select "Marketing Tools"
• Under "Item Promotion," click “Promote Similar Items"

Remember, if you do opt out, your relevant items will not appear on other sellers’ item pages.
 

Regards,
The eBay Team