Why does it have no fees?
Is it under $20? You are right.
Is it made in a NAFTA country ? You are right.
But
If it is over $20, you may be charged sales tax and duty plus a service fee. Couriers and commercial carriers will ALWAYS charge this. Canada Post is ..... lax about it.
If it is used, there is still sales tax. You also pay sales tax on a used car, for example.
If it is imported from the USA , but was made in China or Italy or Angola, it is taxable and dutiable.
All carriers including Canada Post charge a service fee for brokering your imports. This varies from a minimum of $4.95 from the Global Shipping Program to $25 or more with UPS Standard. Canada Post charges $9.95 up.