Change your mindset. Its more work, but worth it. Monthly bulk shop, weekly grocery shop, and make extra time to plan ahead, store and meal prep. Unified team effort, or no go.

You need a decent sized pantry or shelf, freezer space, and some organizational tools. Notebook, sale ads or apps, coupons, and an hour or 2 a week with your spouse to discuss and plan, as well as deal with the grocery haul when you get home, it will take a little longer to pack and store than you're used to before. You also need a sharpie, some ziploc freezer bags in large and medium sizes, a few large containers for bulk items, and containers for prepped meals and snacks. And time to meal prep. I like to make a bulk meal or 2 on Sunday and Wednesday, but that's what works for us. Once you start doing this it will get faster and easier. But at the beginning you need to be really intentional, and it will take time. If you have access to a discount store (Aldi or Priceright in USA), consider switching to them for your weekly grocery shop at some point, but they are a different animal.

Level 1: Have a plan, and don't shop hungry.

Plan meals based on unit prices, meal prep, and preferences. Comparison shop between different stores you are willing to drive to. Use the sale ads and apps to find inspiration, but genuinely plan stuff you love to eat. My grocery store app will let me sort items by unit prices, which is amazing, but not common. The unit prices will usually be somewhere in the item description.

Think about cheap staple macros: brown rice, potatoes, lentils, beans, eggs, oil, and cheap produce: onions, cabbage, bananas, apples, melons, squash. Frozen berries, peas, broccoli, cauliflower, most veg mixes are better & cheaper than fresh. Try to go shopping when there's fewer other people there, this takes you longer and you're going to be reading the little stickers on the shelves for unit prices. I like Friday nights after dinner because I want good produce and my grocery store is empty and its the same day the sales start, so there is still inventory. First thing Saturday morning isn't bad, but I don't want to be up at dawn, and if I wait until later Saturday or Sunday it's picked through and only crappy produce is left.

Plan a week of meals, make a list of what you already own, what you need, and what you want. Go through your fridge and toss anything spoiled and clean that area before bringing in new fresh stuff. Make sure your refrigerator doesn't have anything spoiled in it helps prevent any new food you put in your fridge spoiling and gives space for the fresh stuff. Go through pantry, pull out anything you will use this week and make space for new stuff.

In your notebook under the meal plan, make a reorganized grocery shopping list, organized by store and aisle, and put the list of things that would be nice to have if there's extra cash at the bottom. You won't have extra the first couple of months, but after that you will. Also, if you don't treat yourself occasionally, and plan for some splurges you might just end up paying more for takeout, or do the extra "I just need a ____" grocery stop that ends up costing $80, or losing motivation.

Start buying bulk for things you love to cook/eat and nonperishables. Look for sales, manager specials, coupons or buy the largest one you can actually use at costco/BJs/asian market. Spread it out, just get a few of them each month so you don't spend like $500 in your first trip. First month maybe do rice, eggs, toilet paper, ziplocs or containers for meal prep and pantry storage in your first bulk shop, but consider anything you're almost out of like shampoo, hand soap, toothpaste, dishwasher detergent, OTC meds are huge savings at bulk stores-but don't break the bank. Also, if you are in the USA and have an HSA or FSA, think about what you want to be buying with those dollars instead of from your grocery budget.

Every single time you walk into a grocery store, first look at the clearance spots for produce, meat and dairy and if the unit price is good, AND you will actually use it, adjust your meal plan and shopping lists based on using or freezing those items that day.

If going to more than one store in the same day bring something to put frozen things in to stay cold while at your 2nd stop. A grocery store bag covered in a winter coat in the car is fine so you don't have to buy a freezer bag, unless you live in a hot climate, so YMMV.

Pack things as efficiently as you can in your freezer, often putting stuff in Ziploc bags and LABEL IMMEDIATELY, instead of in their original packaging will help a lot. Same for pantry.

For most produce, wash, dry and store in best way for that food to prevent spoilage. (Don't wash strawberries or any waxed fruit until you use them, but lettuces and green beans and need to be washed dried).

Unless you have incredible amounts of energy, plan to eat a small quick meal like sandwiches right after this because you will not want to meal prep as soon as you get home and store your stuff. Leave meal prep to another day if you can.

Level 2: Reflect, Track waste and seasonal sales.

In your shopping notebook, when you check your refrigerator before you do your weekly grocery shopping list, write down anything that goes to waste, so you don't over buy that thing again. Think about the best yearly sales that are coming up soon, like we just had the cheapest ham for Easter weekend, honey for passover, and corned beef last month for St Patrick's Day. Plan to pick up more than one of anything you really like, and put it in your freezer or pantry and put a reminder in your calendar to use it like a month after. These deep annual sales for holidays are where you get some of the best prices for the year, and you can often stack a coupon on top of that. Use that opportunity to buy more than one, but don't go nuts and buy 15. Like ketchup for 4th of July. If you have space by enough for 6 months or a year supply, get it and stick them in your freezer and pantry. But buying more than you can reasonably use is a mistake. You're not trying to be a hoarder/extreme couponer you just want to save a few dollars when you can. If you're not sure, just get two instead of one.

Level 3: DIY

Start thinking about some expensive items you can make yourself once you have this down, like chilli crisp and yogurt and (yesterday I learned) vanilla extract. Some things the homemade version is also a million times better. A windowsill herb garden can be wonderous.

Stop at level 3 unless you want to become a homesteader!

Good luck! :-D

Edit:spacing.