The easiest way to track the value of NFTs is to use the "NFT" tab on CoinGecko or CoinMarketCap. These authoritative sites will give you an overall read on how the NFT market is doing and what blue-chip projects are trading at.
You could also browse sites like OpenSea or Rarible to check out what the NFT landscape is looking like. Scroll through popular projects like Bored Apes Yacht Club, The Sandbox, or Decenterland to get an impression of the current NFT market.
To figure out your NFT's "fair price," you'll have to factor in other features like their scarcity, who created them, and how long they.ve been around. If your NFT is famous, on top of a popular video game, or connected with a pro sport or celebrity, it should drive up the value of the project.