I agree with all of the tips offered by @littlemouse
To take it a step further…
Go on a diet exclusively on whole food plant based foods based on healthy starches (sweet potatoes), whole grains (brown rice, barley, oatmeal), dried beans (high in protein) bought in bulk, seasonal fruits and vegetables when on sale. Drink only water or teat and don’t drink you calories (soda, juices, Starbucks coffee). Then plan your meals and meal prep for the week. You can easily manage a food budget of under $100 a month for two. My wife and I did this for three months. Now we allow for a slightly larger food budget of $500 a month, which is still much smaller than average. Eating this way is not only cheaper, but way healthier.
Of course housing and transportation are the biggest expenses. If possible, try to move to a lower cost of living area, a smaller house, or a place with less rent. With transportation, if possible walk/bike. Or trade in your car for a cheaper one that is more affordable.
Clothing is an expense too. Try not buying clothes anymore, a “no spend on clothes challenge”. We are doing it. People don’t realize how much clothes we actually have until we take inventory of everything. Chances are it’s more than enough. And whatever doesn’t bring joy… SELL online and make a profit
Buy whatever you can second hand. It definitely saves money. It is better for the environment (puts less used items in the landfill, and creates a lesser demand for new shiny products). It can potentially be healthier (new products could be made with toxic chemicals that emit volatile organic chemicals “VOC”'s that could be neurotoxic and cause endocrine hormone disruption.
Whenever possible, DIY. Have house maintenance problems? If you can, fix it yourself. Don’t hire a house keeper or cleaner, just be a clean minimalist and do it yourself. Don’t buy shampoo and soap, just buy Castile soap and DIY make it yourself. Don’t buy toxic cleaning products with harsh chemicals; DIY and make your products out of dilute white vinegar or dilute isopropyl alcohol. DIY toothopaste using coconut oil, baking soda, xylitol, peppermint essential oil (potentially healthier, and makes my teeth super white). DIY hair cuts.
Be a conscious consumer. Try not to buy anything unless you really need it. If you need to buy something, maximize your return by using a cash back credit card and a cash back shopping portal. You can guarantee getting at least 2% of savings in the form of cash back.
Cut cable, TV, gym membership, and other necessary services of luxury. Just go outside, go run, go hiking and enjoy the sunshine. Most people are vitamin D deficient and can use more sunshine to brighten up their lives