Bill is trying to decide whether to make blueberry muffins or raspberry muffins. Blueberries cost $5.00 per 6 ounce carton and raspberries cost $3.00 per 8 ounce carton. If Bill is going to make 4 batches of muffins, and each batch takes 12 ounces of fruit, how much money would he save by using raspberries instead of blueberries?