Add-on deals are in-shop promotions, where you can get discounts for buying add-on products or get gifts with purchase of certain products from the same seller.
To find an Add-on Deal, look out for the Add-on Deal or Free Gift labels when you're searching for products.
Enjoy discounts with add-on products or get free gifts when you add more items to the main product. You can do so by selecting an Add-on Deal product > View More under Add-on Deals > Select items with the Add-On/Free Gift label > Select variation (if applicable) and Quantity > Select Confirm > Select Add To Cart.
There are limits on the number of Add-on Deals you can buy within a shop. Check the purchase limit set by the seller when you're selecting Add-on Deals.