You can be your own broker agent in Canada
There are ways to do it and the carrier can’t stop you
They hate it
And they will try to stop you, they will lie to you
But at the end of the day they have to let you broker the parcel yourself
And the actual fees are trivial

Myself I usually just drive the parts across the border as I do road trips several times a year and I keep a list of nice to have shopping items in my phone for the next time
-s