How much starch are you okay with? Potatoes, rice, seasonal squashes, and green plantains are very budget friendly in my area. There are a million ways to prepare them so nobody gets bored. For best satiety I eat an amount roughly equal in size of the meat and never outside of meals.
For beef: grass-finishing is lovely but not as crucial as hormone/antibiotic-free. In some areas the best supplier may not be certified organic (you could google the individual brands and make a judgment call). Buy things with two uses, e.g. fatty ground beef where you save the drip and saute green cabbage later, or less popular bone-in cuts and save the bones for soup. The "complementary protein" of bone stock is no joke--it's way more filling than its calories would suggest.
Pork: I adore shoulders and rumps but quality is important so I don't buy it as often. I buy quality bacon often enough to keep some saved fat in stock.
Eggs: Pretty important IMO. The best eggs are true foraging birds (NOT vegetarian). Opinions are split on the flax meal used in o-3 eggs but I consider it a good signifier that at least it's not a useless battery egg so I dig them.
I don't buy any organic plants unless they're significantly fresher/nicer looking. I depend on a lot of conventional bananas, carrots, and onions. Rinsing leaves, stalks, and berries is probably wise.
I actually find nuts/seeds not very filling and expensive so I use them for garnish only. As a fat source I'd place them a notch below animal fat and oily fruits and would rather snack on something like raw veggies dipped in sour cream or guacamole, but if the kids love them have at it.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starch fruits, vegetables, meat fat, dairy fat, oil fruits
Some: cured meat, dairy protein, sweet fruits, rice, pulses, tree nuts, oil seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, refined oils, peanuts