I feel like I would be cheating by participating since we've been doing this for... 10+ years now, since neither of us has ever had a car, and we both prefer my cooking to other food options. But whatever.
Last weekend I bought all our fresh ingredients (big assortment of vegetables, tofu, sausages, seitan, and pasta) at a market in Chinatown via walking, and we took transit out to a discount grocery to stock up in a few staples (yeast, soy sauce, bagels, and some personal care/cleaning stuff). Over the weekend I made tofu stir fry, veggie burger stir fry, curry seitan, pasta with sausage, vegetable/sausage pot pie, bread, oatmeal muffins, and blondies. That's all our food for the week - we rotate through things so we're not eating the same meals over and over. That's a pretty typical week. I think we spent about $35 between the two stores.