I noticed as a Canadian site, Kobo was applying the GST to book purchases. I also noticed that when I have been purchasing books from Books On Board that I have also been paying a 'transaction' fee. This transaction fee is close to what I pay for GST but still annoying.
As a Canadian I can't escape paying the GST or PST but I can choose where I buy my books. So most of the time I buy my books from sites that benefit me the most and not the Federal Government. About the only time I buy from Kobo is when I do have a coupon. It's a rather sad situation as I feel that I should be giving my business to a Canadian company. The only times I can think of that it would be to my benefit to buy from Kobo would be if the exchange on the US dollar was unusually high.