回複：謝謝！請問使用US-Mail還要收取duty and brokerage fee嗎？

You will have to pay duty if the product is not made in the USA no matter which carrier/shipper you are using. I am not sure about brokerage fee.

Also, the GST and PST is calculated using the TOTAL of your product price and duty.

The carrier/shipper will charge you this (COD) when they deliver the product to you.