I love shopping at stores like Costco and Sam's Club.
These are the things I typically get at Costco (I can get about 80-85% of our shopping done here for our family of three):
-Berries (fresh or frozen - their frozen blueberries and raspberries are usually priced pretty low)
-Spinach (the bag is huge, but even if you end up throwing some away because you couldn't eat it in time, it is usually still cheaper than buying the small bags at the regular store)
-Big flat of 7.5 dozen eggs
-Cucumbers (comes in a 3-pack)
-Baby portabella mushrooms (2lb pack)
-Bag of bell peppers (6 in a bag, 2 yellow, 2 red, 2 orange)
-Sometimes you can find a big box of sweet potatoes, but not always
-Greek Yogurt (Fage brand 0% is the one I like best. Kirkland is cheaper but not as creamy and has less protein)
-They have a huge bag of organic carrots. I think it is 10lb for $7. I usually just chop the ends off and have them ready to snack on during the day. My husband snacks on carrots all day long when he is at work. Those carrots are always soooo sweet! (not the baby carrots, they are regular carrots)
-Tomatoes - you can get a big flat of 9 (or maybe it is 12) tomatoes for pretty cheap
-Quaker Old Fashioned Oats (buy in bulk and grind them into oat flour)
-Quinoa - they have a big bag or organic quinoa
-Raw Almonds (3lb bag)
-Organic tomato sauce and diced tomatoes (although they are not low-sodium)
-If you have kids, they have these cool squeezable applesauce packets with no sugar added. My 2 year old loves them!
-They have lean ground turkey there, but not extra lean ground turkey
-At my costco, they have fresh chicken breast and the price is a little higher than other places you can find the chicken on sale for, but the cool thing is that they come in a big package....but then the package is split up into "smaller" packages that are already sealed air tight. You can just break off those "smaller" packages and put them straight in the freezer! No freezer burn. You can get frozen chicken breasts too, but watch the sodium level in the frozen breasts.
-Lemons and limes. I buy these in bulk because I always seem to be using them in my recipes and fresh always tastes better!
-Lemon juice - they have two big containers for a pretty cheap price (can't remember exact price)
-Almost all my spices come from Costco. Great quality and cheap!
-Frozen Wild Flounder (they also have good frozen wild salmon, we just catch our own otherwise I would buy it here)
Hope that is helpful! There are probably a few other things that I am not thinking about either right now....