Spot Buy is a feature in SAP Ariba that allows users to quickly and easily purchase goods or services from suppliers that are not part of their existing supplier network. It provides a streamlined process for ad-hoc purchases and helps organizations quickly find and engage with suppliers to meet their immediate needs.
This feature is to provide a way for users to make specialty purchases through SAP Ariba, which they would otherwise have to fill out internal order forms through a procurement department or to purchase the goods on their own and then create an expense to be reimbursed by their company. In other words, when creating a noncatalog item, you can first search the Spot Buy catalog and request the item that you are looking for there.