I love costco for some of these things. (if you have a winco in your area, they also have mad low prices).

Staples for us:
water pack (truely, no veggie broth) tuna
celery, scallions, romaine or salad mix
sugar-free bacon(out here, the safeway chain's store brand of low sodium bacon is actually sugar free)
a roast - be it pork or beef, that you can get slices of to use as lunch meat, and get several meals out of.
ground beef in bulk
eggs!
cheddar cheese (if I could only have one flavor in the house, we'd pick cheddar)
cabbage (I make a mean cm cole slaw), plain boiled cabbage tastes sweet and good to me - plus you can add it to homemade broth with a bit of meat and call it soup
plain ground pork - to make your own pork sausage - you can then adjust the salt to what you prefer/can have, and season it as breakfast sausage (I have recipes, sure there are lots on here) or Italian seasonings.
a whole chicken - boil up the back and wings for broth, use the thighs as their own meal, chicken breast - can roast up, carefully slice for sandwiches, or make a cm chicken salad, or shred and make a rm dish with. Drumsticks can be made up as fat cm chicken wings with hot sauce, butter and bit of garlic (or however you want to season them)..plain tabasco, or Frank's hot sauce have no sugars.
green bell pepper - nice for salad, or sauteed with eggs, or as part of a chicken dish..just lots of uses.
when all else fails, if you find steakums on sale, though quite greasy, they are quick, easy and delish.

hth!