Breakfast:
Steel cut oats - $.89/lb at Whole Foods in the bulk bins
Dried fruit (raisins, cranberries, blueberries, pineapple, papaya, etc.) - somewhere between $1.50/lb and $8/lb, either in bulk or pre-packaged in the bulk section at Whole Foods
Walnuts or pecans - $6-$8/lb from the bulk bin at Whole Foods or Nob Hill
Brown sugar and butter - small enough quantity that it barely counts. Probably $.25 each day.
Total price for breakfast: Probably a buck or two...I've never added it all up. It's surprisingly filling and enjoyable. I sometimes skip lunch, if I know my girlfriend will be home early, or if I'm meeting someone out for dinner.
Lunch:
Rice - cheap as free. I have a rice cooker ($20, or $179 for the "fuzzy logic" one that I now have that can do brown rice), so it takes little human time.
Vegetables stir fried, or in a fried rice - Whatever is cheapest at the Nob Hill or Milk Pail. The cheapest stuff is what is in season and tastes best and is most healthy. So, that's what I buy. It's about $2 per day for lunch.
Cashews or tofu or eggs for protein (I'm vegetarian). About $.50 per day.
Sometimes, I'll make enough hummus and stack of flatbread for two or three days worth of lunch. That's super cheap. About $1 per meal. One <$1 bag of garbanzo beans is enough for a huge bowl of hummus, though the tahini and spices can add to the price a bit.
Total lunch price: Probably about $3. Prep time about 15 minutes.
Dinner:
Girlfriend is home for dinner, so she determines that meal mostly. It's either eat out, order a pizza, or eat various crappy carb-filled meals. Pasta is a staple. Mostly still pretty cheap when we eat at home, even though a lot of it comes from boxes.
Add a bag of apples or other fresh fruit and some various nuts from the bulk bins for snacks, and you've got a balanced healthy days worth of food.
I tried ordering from Amazon, but ended up never having all of the stuff I needed, anyway. You've gotta have milk for boxed mac and cheese. Eggs for a lot of stuff. Fresh cheese for good sandwiches. Bread (and I like the good stuff...crusty sour dough and such). It just doesn't allow one to build complete meals. I have been known to "wing it" by picking up a few fresh items from the asian market that's walking distance from here, and buying large quantities of the dry goods every two or three weeks...in order to minimize time spent shopping.
But, the fact is, that I'm less productive when I fall into a rut of being at home all the time. Sometimes dramatically so. Getting out helps.
Exercise, social interaction, some downtime...make a trip to a grocery store!
If you are being frugal, it is almost certainly better to shop around locally.
I will not sacrifice exercising for a startup; for me personally it is counter-productive. The time spent exercising pays great dividends in my energy levels throughout the week.
I will and have sacrificed spending money, some social interaction, and various other things.
To each their own though, I just feel that grocery shopping is trivial, only takes a few minutes, and has it's benefits. Not to mention you could listen to a tech podcast or think about an algorithm while shopping/running into other carts.