Toast sunflower seeds in the oven for 10 to 15 minutes at 425 degrees Fahrenheit. You can use sunflower seeds -- or almonds, pistachios, or walnuts -- as a replacement for the pine nuts traditionally used in pesto. Not only will this slightly change the flavor of the sauce, it will make it substantially cheaper.
Replace the pine nuts, if you wish, with sun-dried tomatoes. You can either process the sun-dried tomatoes with the other ingredients of pesto (basil, garlic) in a food processor, or you can stir them together to create an entirely different kind of sauce.
Be creative, and replace the basil with different leaf and herb combinations. For instance, you can use spinach, which has a much heartier flavor, or cilantro for a more exotic taste. Alternatively, you may replace the basil with arugula, or with a combination of leaf parsley and spring onions.
Tweak the basil taste, should you choose to leave the basil in the recipe, by adding green onions, fresh chives, marjoram or thyme. You may either marinate the herbs with the rest of the recipe, or you may pound them together or grind them in a food processor.