Begin with cost per meal, not package price
A larger package is only a bargain if it gets eaten. Compare the number of servings you will realistically use, then consider shelf life and waste. Dried lentils may be inexpensive per serving; canned beans cost a little more but save time. Eggs, milk, yogurt, tofu, canned fish, and frozen edamame can each be strong values depending on local prices.
Use protein anchors
Choose one clear anchor for a meal, then build around it. Lentil chili, eggs on whole-grain toast, yogurt with oats, tofu stir-fry, bean tacos, and canned salmon sandwiches all combine protein with other useful nutrients. Mixing animal and plant foods is optional; variety across the week matters more than constructing a perfect plate every time.
Make convenience work for you
Convenience is not a nutritional failure. No-salt-added beans, frozen vegetables, microwaveable grains, and canned fish can reduce both preparation time and food waste. Rinse regular canned beans if you want to reduce some sodium. Keep two emergency meals available for nights when cooking will not happen.
A simple shopping pattern
Buy two breakfast proteins, two lunch-or-dinner proteins, and one shelf-stable backup. Repeat ingredients in different forms: lentils can become soup, curry, or pasta sauce; eggs can become breakfast, sandwiches, or fried rice. This creates variety without requiring a long ingredient list.