Compare the amount of lean meat, poultry and fish servings you get per pound instead of just cost per pound. Buy lean cuts of beef and pork. Watch for sales on bulk family packs, and refreeze them in portions you will use. Chicken and turkey often cost less than other meats, and they have less fat and fewer calories.
Fish is mainly low in saturated fat, the fat which tends to raise blood cholesterol.
Frozen fish often costs less than fresh fish. Buy fish fillets, and bread and bake them yourself. Coatings on prepared fish sticks add to their fat content, their weight and their cost. Use less expensive forms of tuna, such as flaked, in sandwiches and mixed dishes when appearance isn't important. Flaked tuna costs less than chunk.