While you decide to create NFT marketplace of your own, being mindful of your niche and a proper understanding of the existing marketplace is crucial. As the NFT marketplace is where all the trade and transactions will occur. One should be careful with its development in the platform's security, transparency, and decentralization. There is no fixed answer as to how much it will cost to create NFT marketplace. However, they can vary with the requirements like,
UI/UX design for the platform
Integration of technologies
Integration of third-party APIs
Technology stack, etc.