I was kind of thinking about this as well! But in the end I kind of thought it would be something I would just build for myself. As in I often go to a few different grocery sites in nyc as ones super close, another is 5 mins further. And then there’s random little markets that have better deals on fruit. I walk by them all the time. Could perhaps be quite easy to make a little front end where you fuzzy find the food item with search and select qty options and insert the price.