Answers to some of the questions you have

Like most things on the internet, our default pricing is USD. Pricing is displayed in USD, unless you explicitly select a different currency to display. 

You will be charged in USD unless you’re shipping address is to a valid address in Canada, in which case you will be charged in CAD.

This is always a great question, and for the most part our current answer is no. However some exceptions can be made to this and all duties/taxes are the responsibility of the recipient.