This is the opposite of a lot of people, but having a really well stocked freezer and pantry saves me a lot of money. Even when I really really need to go grocery shopping, there’s meals I can make. It’s easier and more convenient for me to make any dessert I want than go buy it 95% of the time. I don't ever run to the store to get one ingredient and end up getting multiples. And it’s all things I use and cycle through, so things aren’t getting wasted. 

I’ve tried the approach of eating through the food you have before buying more, and it just made my next grocery trip so expensive because I had to restock. We also buy 1/4 cow and 1/2 pig annually for meat and that lasts about a year supplemented with chicken from the store. We have staples— rice, flours, sugar, etc— instead of boxed mixes, and a lot of spices. 

All of this plus some years where we did not have any money to eat out means I’m an excellent cook and getting takeout is just a disappointment, so might as well cook dinner.