$100.00?! That is insane! What are these people doing? There are a few simple things that everyone can do to preserve all that food.
I shop a couple of times a week and I do buy in bulk, but I have learned a few tricks along the way to save all that stuff from going bad before I get around to eating it.
The first thing is that you HAVE to own a deep freeze - even if you live by yourself get one! I have a 7.5 cubic foot and it is almost always full. Yes I bake, but there is also a lot of meats and meals that I have prepared myself and frozen in individual portions. I buy warehouse trays of meat and then portion into 1 or 2 portions/freezer bag. I then lay the packages on cookie sheets so that they will freeze flat and take up less room in the freezer. I cook stews, casseroles, chilli and other dishes that make 6 - 10 servings and freeze the portions. These can also be frozen flat in zippered sandwich bags or small freezer containers.
I don't buy the IQF (Individually Quick Frozen) meats and poultry. I find that even though they may be cheaper, the product generally has less flavour and their are often additional additives to increase the shelf life of the product. I also find that by buying the fresh meats and poultry, I can trim excess fat and remove bones and skin if desired. I buy large trays of lean ground beef, turkey or chicken then make them into individual meat loaves, burgers or divide into 1 pound packages and freeze for later use.
Generally, if I open a container such as apple sauce or stewed tomatoes, I only use a cup or so. Rather than allowing it to sit in the fridge for a month or so and go bad, I measure it into 1/2 cup portions and freeze in zippered snack bags that I also lay flat to freeze. Once frozen, place in a freezer bag and return to freezer for later usage.
ALWAYS LABEL AND DATE EVERYTHING IN YOUR FREEZER!
Dairy products are another area where money is often wasted.
Pre-grated and sliced cheeses are a waste of money. You can grate and freeze cheddar and mozzarella (most commonly bought grated). When I open a package of cheese, I carefully open only one end and fold back the plastic shrink wrap. I then slice/grate what I need. Then I pull that wrap back over the exposed end AND wrap the entire piece tightly in a good quality plastic wrap. Keep an eye on the cheese as you use it. Watch for any change in colour or start of mould, If there is any, remove the manufacturers wrap and cut the mould off. A little mould does not mean that you have to throw the whole piece out. Just cut it off and replace with fresh plastic wrap. I have also taken over sized elastic bands and wrapped around the plastic wrap to prevent the plastic from coming undone. As I get closer to the end of the piece, I remove the original manufacturers wrap and cut all six sides of the cheese for the next use. That removes any immediate potential for mould. I also replace the plastic wrap it it is getting torn. Using this method, I can keep a 2lb. block of cheddar or mozzarella for about 6 weeks or so. Cheeses will vary, but I've also kept 1 pound Monterrey Jack and Havarti for at least a month.
Is the milk getting near the end of its best before date? Is there the faintest hint that it is starting to turn? Odds are it is the container that is causing it. I saved a 1.5 litre/quart jar with a plastic lid (It was from Miracle Whip). I washed and basically sterilized the container. When it was completely dry and cool, I poured the milk from the jug into the jar. It should keep for up to an additional week. Yes, you have to be more careful pouring, but it is still cheaper than throwing out sour milk!
Bread and buns going dry or mouldy? When I buy a loaf of bread, I always have it sliced at the store. When I get home, I take out what I need for the first day or two and the rest goes in the freezer. Buns/bagels are sliced horizontally and put in sandwich bags to freeze. Pre-slicing the bakery items is also a great way to save time if you are making a lunch to go. Take it out and make the sandwich/bunwich while still frozen. Put the cold item in the fridge or your insulated lunch bag, It will help preserve the freshness of your lunch. If your eating right away, then pop the slice in the toaster for a minute or the microwave for about 4 or 5 seconds. It will be like fresh from the bakery!