To calculate the unit price of a 120 fluid ounce bottle of shampoo that costs $7.20, we need to divide the total cost by the number of fluid ounces:
Unit price = Total cost / Number of fluid ounces
Unit price = $7.20 / 120 fluid ounces
Unit price = $0.06 per fluid ounce
Therefore, the unit price of a 120 fluid ounce bottle of shampoo that costs $7.20 is $0.06 per fluid ounce.