The green prices are for goods that are bought with health, sustainability, and kindness in mind. The fruits and vegetables are organic or sustainably raised. The beans, flour, grains, and spices are organic.
For the vegetarian recipes in Wildly Affordable Organic and the earlier challenges from before the Cook for Good went vegan, the eggs come from local, pastured chickens who roam around outside and eat whatever bugs or leafy things that they can get, plus whatever wholesome feed the farmer gives them. If these aren't available, the eggs come from the big suppliers who raise free-range chickens on organic, vegetarian feed. Organic cheese has become more common, so the "green" cheese is at least free from Recombinant Bovine Growth Hormone (rBGH), also known as Bovine somatotropin (BST). Cheddar and Mozzerlla are organic.