If you like to save calories on recipes with ground meat or are on a diet, you should substitute mixed ground meat with lean ground beef. On average the mixed ground meat is cheaper then lean ground beef but it doesn't matter as you only need a small amount.
If you are planning on a party and need a larger quantity of ground meat it pays to buy beef and pork and grind it yourself using a meat grinder. Find more recipes with ground meat in the categories meatloaf, fried dishes and BBQ. You also should find helpful suggestions in the categories potato casseroles or party recipes. Ground meat is easily perishable and you should cook it right away. After ground meat is cooked you can keep the burgers, meatloaf or other dishes in the refrigerator until the next day.