Hello,
Yes, the custom will charge GST on the value of the products. You should contact the custom department to find more. For example, I bought $100US cables, the exchange rate would be $130Can and they tax the GST on this amount. Fedex, however charge the brokage fee stupidly high. I bought 2 used cables with the sellers help declared as gift $100. One had sent through US postal the other through Fedex. At the end the one with the Fedex I had to pay $45Can on fees, GST, the one came through Canada postal and had no charge. So I still don't know how the system charge on the taxes or fees, so far I am happy with postal, they do charge the GST or PST accordingly as products declared as new, used or gift plus a small amount handling fee.