PSN users in Canada will have to pay an online sales tax on their purchases starting January 2019. This was confirmed by Sony in their official support FAQ.
PSN users in the United States are already paying online tax on purchases, although this only applies to certain states while others are exempt from it. Now Canada is going to soon join this list as confirmed by Sony.
PSN users who have an account in Canada will have to pay a certain amount of sales tax from the next year. The official FAQ has listed the following statement regarding this new sales tax update.
In certain areas, states/provinces and local laws in the U.S./Canada, require PlayStation® Store to collect applicable sales taxes. In order to comply with these laws, PlayStation® Store began collecting sales tax in certain states in the U.S.in April 2016 and will begin in certain provinces in Canada in Jan 2019.
Since this is required by law, it will be applied to every PSN purchase. You should start paying your taxes like a good citizen although it might increase the price of digital purchases even further, it is a price to pay in such a case.
There is no percentage given with this update, but it is possible that a standard tax percentage that already applies to digital sales will be used to tax the users on PSN.