Stan and Francine want to make perfume. In order to get the right balance of ingredients for their tastes, they bought 3 ounces of rose oil at \($2.04\) per ounce, 5 ounces of ginger essence for \($2.86\) per ounce, and 5 ounces of black currant essence for \($2.19\) per ounce. Determine the cost per ounce of the perfume.