Next to nothing, there are millions out there - ultimately they are used for training cooking to 120, and that's it. It's all about the delectable foods here. you might get 1 gold per 2 fish steaks from someone looking to train cooking to 120.
With 120 cooking, you can use rarer materials from forensics skinning, and fishing to make delectable foods, which are used for faster regeneration (health, stam, mana) - those will sell for about 100 gold per - and last I think 60 minutes.