Operating a publicly accessible purchasing system including receiving, on a receipt date, from a purchaser, in a publicly accessible purchasing system, a deferred purchase request (“DPR”) for an item to be purchased; identifying a vendor; and issuing, in dependence upon the DPR, a purchase order to the vendor on a date subsequent to the receipt date. In some embodiments, a DPR includes an item identification for the item to be purchased, and identifying a vendor further comprises identifying a vendor in dependence upon the item identification. Some embodiments includes selecting a vendor in dependence upon vendor item prices. Some embodiments include selecting a vendor having a lowest vendor item price for the item to be purchased. Embodiments include selecting vendors in dependence upon purchasers' indicated maximum prices, in independence upon information in purchase orders previously issued to vendors, and in dependence upon proximity of a vendor to a purchaser.