I recently purchased a product from a USA online seller, for which the seller confirmed USD 99, which costs me around 135 CAD. They charged me 5% GST on my product, as the customs duty tax is 8% and the handling fee is at 9.95%. I decided to check the prices associated with the customs duties for each product using the Canada tax calculator. The tax calculator determines the import tax for different provinces of Canada, which is free to use. 

https://hstcalculator.onl/