Hmm... insuficient information...
Generally speaking, the receiving carrier on the other side of the border pays the customs clearance fee, which for Canada Post is $8 and for USPS about half that. Commercial vs non commercial has little to do with it.
I commonly ship and receive items up to $2k both Expedited and ExpressPost and I've never heard of such an occurance, so there is a missing piece of information, perhaps you are shipping controlled substances subject to penalties ?
Common carrier parcel services like UPS Purolator etc, charge what the market will bare, which is $40.oo plus applicable taxes for UPS, not sure what Purolater charges these days, something more disgusting probably 😉