Offer Valid on like for like items. Items can be mixed across different designs, as long as they are the same price.
E.g.: Add a 'Surf's Up' harness to your cart, and you can add any other harness design which is within this offer & of the same value to your cart for free. Free items will be shown in cart at checkout automatically. Carts with multiple items with different values will receive the cheapest item for free as part of this offer.
