These are tokens that have been designed to be unique. They are used to identify a specific owner. Once you own the NFT, you can then use it or sell it as you please. You could set any price you want on the Marketplace.
Note: if you sell your NFT, you will lose the additional features provided by the NFT.

Non-fungible Token (NFT)

A non-fungible token (NFT) is a type of cryptographic token that represents a unique asset. NFTs are tokenized versions of digital or real-world assets. They function as verifiable proofs of authenticity and ownership within a blockchain network. NFTs are not interchangeable with each other and introduce scarcity to the digital world... --> Read more