Maybe someone mentioned this but we buy our almond flour on amazon.com - it's cheaper than the grocery store and if we do subscribe we save 20%. That said, I try not to do a lot of baking. We do do some grains occasionally - for instance, we do popcorn as a snack sometimes. It's very cheap and that's mostly why (though it's also delicious). We don't seem to have serious issues with corn, though.
Ok, here's my other thoughts, though I haven't gotten through this thread yet.
My kids like to snack on frozen peas, which is fairly cheap - they eat them like popcorn.
I also started throwing liver in whenever we do something with ground beef to make it go farther. Healthier AND cheaper... we were surprised how unnoticeable it was in things like taco meat because of the seasoning on it.
We also keep hard boiled eggs in the fridge constantly to snack on, though my kids have gotten bored with it.
We also have sardines for lunches, sometimes...
Actually, I'm really looking forward to fall/winter because most of the stuff we eat that time of year is soups and stews which I can make for much cheaper than our summer meals - we try to eat seasonally, but fresh summer veggies, fruit, etc. are so expensive! A typical summer meal is grilled meat + veggie + veggie or grilled meat + salad. Winter is more like we'll roast a chicken one day and then the next day we have soup from the carcass and leftovers. Two meals in one, basically...