NFT stands for non-fungible token. A short answer a NFT is an image or thing that exists in a decentralized network accessed by one address and distributed on a blockchain usually for a cost. Many NFTs are selling for $1,000s. Digital and offline artists love NFTs because they can easily sell their art. There are NFTs for famous paintings, baseball cards, etc. It is online collecting. Two currently popular sites for non-paying NFTs are Opensea and Mintable.
Traditional NFTs pay if you sell them. A Paying NFT is setup to generate profit to the owner so they do not want to sell it they want to own more and better to earn more! Paying NFTs generate a profit by minting new tokens, through shared liquidity, and various ways. They can be part of a blockchain based game or other blockchain projects.