This document is a guide designed to assist buyers in evaluating AI vendors before making a purchase decision. It outlines a series of questions and considerations that should be addressed during vendor demonstrations to ensure a comprehensive understanding of the AI product being offered. The checklist emphasizes the importance of understanding the AI's functionality, data flows, compliance with the EU AI Act, explainability, human oversight, and contractual protections. Each section provides specific questions to ask vendors, as well as potential red flags to watch for during the evaluation process. The guide aims to enhance the buyer's confidence and knowledge when selecting an AI solution, ensuring that all relevant aspects are thoroughly considered. It also highlights the necessity of cross-functional collaboration among different teams, including legal, engineering, security, and procurement, to ensure a well-rounded evaluation of the AI vendor.