Depending on what you are shipping use US Postal.
UPS and Fedex charge huge fees to cross the border, sometimes exceeding the value of the shipment.
The tracking of packages with US Postal is not that great, but there are low (sometimes none) brokerage fees and you pay taxes on the stated value of the item.
DHL is another one that I have had luck with as well. They even leave the package in a safe spot or with the neighbours and send you a bill later, again lower or no brokerage fees and only tax/duty on stated value.