When customers are already purchasing relevant products, businesses can make it as easy as possible for them to buy more products by upselling and cross-selling products on product pages, Ajax carts, and cart pages. For example, when selling candles, businesses can offer a wick trimmer directly on the product page to complement the existing purchase, or when selling sneakers, businesses can offer socks as a complementary product. This allows businesses to serve the perfect complementary product at the right time in the right place when customers are already making purchases.