Out of curiosity, what are you buying? I cook for a family of three and I buy like $100-150 worth of food every month. I buy lots of fresh produce (many, many onions), whole chickens or large cuts I trim myself and some cheese or butter. I also make my own stock with a slow cooker, veggies scraps and bones/carcass from the chicken. I also buy my fresh produce at the local, smaller, grocery store. If you want to you can also use beans and peas to supplement protein.

I also save money on spices buying them whole (like whole pepper corns) by the bag from local specialty grocery stores, bottled spices at the big box store are a scam in comparison. When cooking I scoop all the spices I need and grind them in a dedicated coffee grinder, it's really fast.

Also by the cuisines, basic, "base" ingredients in bulk. The kind where you can make most other sauces and dishes with. An example for Asian cooking is soy sauce, honey, oyster sauce, fish sauce, sesame oil, rice wine vinegar. The combination will let you make a large variety of sauces in that cuisine.

Also freeze finished meals so you never need to get door dash.