I was going to make a thread about Sam's Club last night but posting was broken.
Sam's Club is total win.
Buy rice, beans, potatoes, carrots, raisins, cans of tuna, celery, mushrooms, bell peppers, avocados, bananas, oranges, eggs, pork shoulders, etc. All of this stuff can last a fairly long time if you just do a little reading about storage first.
Put your potatoes in a paper bag poked with holes in a cool, dry place. Bananas on the counter. Eat them up within a few days, freeze them for smoothies and sundaes, or mash and add to banana nut bread. Oranges, celery, eggs, and carrots last forever in the fridge.. Rice, beans, raisins, cans of tuna...all shelf stable. Pork shoulders should be divided and frozen.
Stay away from the chips and cookies. Basically avoid the aisles and just stay at the produce and meat.