Timely topic to run across. I would have saved money by eating out today. (Well, not what we ate, but still...) I stopped by Berkeley Bowl and got a couple of decent size (but not huge) grass fed ribeyes and grilled them quickly over coals, and we also had a couple of small artichokes and other grilled vegetables and tortillas. And it had been a while since I had a good piece of steak. So, while the meat was about $32, it would have been that much + each at a restaurant, and wouldn't have tasted any better.
When we eat out, we usually share a starter, each get a main course, and then sometimes share a dessert - usually plenty of food for 2.
When we cook dinner at home, we'll often make enough for me to have a lunch or two during the week.
When we have leftovers, I can usually repurpose them into something good.
Our simple fact, which isn't particularly money-saving, is that we rarely have extra "fresh food" in the house. There's very little in the freezer, the places we often shop don't have regular ads, and we have a cornucopia of fresh everything always available. On the other hand, there's little waste because we don't stock up on things that are a good price and will rot before they're used.