Embodiments of methods, systems, and storage media associated with height-based item retrieval are described. A product demand determination system (“PDS”) may receive an indication of a product which a customer may desire to purchase. If the product is not available for purchase, the PDS may request information about the desired product. The PDS may then generate a product demand page which may allow customers to provide feedback as to whether the desired product should be sold. The PDS may also determine, based in part on the feedback, whether the e-commerce system should provide the desired product for sale based on various market considerations. Additionally, the PDS may be configured to receive seller information from one or more sellers who may wish to sell the desired product or service. Other embodiments may be described and/or claimed.