Facebook Marketplace exists to provide a platform for users to buy and sell items within their local community. The goal is to create a more convenient and trustworthy way for users to engage in local commerce. Facebook has a large user base, and Marketplace takes advantage of this by allowing users to easily find and connect with local buyers and sellers. The platform is free to use and integrates with Facebook's existing infrastructure, making it easy for users to post and discover items for sale. Overall, Facebook Marketplace aims to provide a safe and accessible way for users to engage in local commerce and build connections within their community.