IMO, there is an important prerequisite to reaching "Eating well on a budget" - willing to spend time on food preparation. Willingness creates/improves capabilities, and it's a positive circle.
I learned how to cook when I was an elementary school student simply because I wanted to save the money my parents gave me for the next day's lunch for pocket money. My parents are party animals and love all kinds of social activities. They were always outside for friends and left money for us to buy food from the store. Our fridge was always full of leftovers from parties or ingredients from their friends.
So, I learned how to handle all kinds of ingredients when I was that young. Motivations appeared, and then actions followed. DD is a different story since I can cook pretty well. Although I tried to teach her, it won't really work unless she finds her own motivation one day. She appreciated whatever I cooked, but she was NOT willing to spend time doing anything similar. Well, it's not "never," but I will say, once or twice per year, that she will cook something "balanced" for herself from my perspective.
For example, I had six chicken thighs and one Gilt-head bream today. DH and DD will never buy any fish like this. I cleaned it in a bucket and brought the used water to the newly transplanted shrubs.
Part of the tail and chin became food for our two cats.
Some bones became food for cats/dogs, and the rest would be used for making broth with the fish head.
We love boneless chicken thighs - crunchy, juicy, and satisfying.
Same for veggies and fruits - besides the orange peels reported to the two fridges, most of the unwanted became food for the hens.
Seasonal and local ingredients are always cost-effective. For example, leeks are very affordable here now. I got these huge leeks for less than 3 Euros. It's a lot of food, and they are very "multi-functional."
When organs are acceptable, there will be even more choices and combinations. We had a hot pot during the weekend. Sliced pork butt, liver, heart, some noodles, and mixed veggie plate guarantee a warm and cozy evening, even though it was cold and rained badly outside.