The problem about this domain is that food aren't normally sold online unless it's a huge grocery store such as safeway. I'd appraisal this at Mid $XX.
"green food" alone has a lesser search count and you're adding the word "buy" to it. the domain sounds cool but i think a low-mid $xx is all you get without a website. with a decent webpage and some links here and there it can be worth low $xxx good luck