"Perfection is the enemy of good enough." PB, even cutting corners, is not a cheap diet.
Buy CAFO meat and conventional eggs.
While not pure, I'd say if you have to add some non-animal calories, aim for sweet potatoes, lentils, and white rice. Frankly, I'm not adverse to regular potatoes for a maintenance diet, as compared to weight loss. Do you like yogurt? Make your own. If you leave the whey in, you'll get a gallon of yogurt for $3.
Do whatya gotta do, just hew as closely to Perfection as YOU are able to.