eBay Store's Cross Promotion
tools help you show the right product to your buyers at the right time. Cross-promotions help you sell more because they prominently display the other items you're offering, thereby encouraging buyers to purchase additional items or higher-value items.

Increase your sales by cross-promoting:
• Higher-value items when a user views your listing
• Similar items when a user views your listing (for example, a different size or color)
• Complementary items when a buyer bids on or wins one of your items
• Accessory Items that go with the item your buyer just purchased
Setting up these cross-promotion relationships is completely free for sellers with an eBay Store subscription. Here's how it works:
• Every Store seller has default cross-promotion rules to promote items in the same or similar categories. You can change your default rules to promote more targeted items.
• When you list an item in one of your custom Store categories, cross-promotions are automatically selected based on these default rules.
• When a user views one of your listings, four additional listings (based on your cross-promotion rules) will be shown below the item description.
• When a buyer bids on or wins your item, another four listings will be shown on the page they see after bidding/buying.