What I do is I walk into the bulk section of the grocery store (I shop at Sprouts which is one of those whole foods/farmers market type of stores)… I buy a couple pounds worth of nuts (this may last a couple weeks depending on the quantity), whichever are on sale (cashews, almonds, walnuts, mixed nuts, etc). Then I buy a large amount of oatmeal in the bulk section as well. All of this is really cheap.
Next I head on over to the meat section, and I buy whatever meats are on sale (ground beef, various steaks, stew meat, pork, chicken, fish, etc). I usually end up buying mostly beef, which has more bang for its buck too in terms of calories than chicken. Again, this is fairly cheap, since I only buy what is on sale.
From there, I look into the produce section and buy some vegetables & herbs to match up with the meats for meals. I also buy some fruits and stick to the ones that are on sale, except organic bananas I love bananas and those are a staple. I might buy some frozen fruit as well, such as pineapple, papaya, strawberries, or blueberries.
To finish it off I’ll buy some cottage cheese, natty peanut butter, kosher pickles, olive oil, bbq sauce, spices, or any other small, inexpensive items I may need. I usually go to Trader Joes for some of this stuff, and the frozen fruit, because I can get good deals there on those sort of things.
Long story short I don’t waste much money on a bunch of processed foods or liquids. I stick to primarily whole foods to keep the costs lower, and I cook all my meals. The food tastes great, and I eat a lot of high quality food.