Don't use UPS. They charge too much of a brokerage fee.
Try Fedex or even standard mail.
Most people in canada ask me to ship via USPS Priority Mail. That way they pay the true tax cost and not UPS's brokerage fee.
Taxes on packages are based on declared value.
There is no LEGAL way to get around paying the tax.
I've heard you can mark the box "FOR REPAIR" or "NOT FOR RESALE" and not pay any taxes. Also you can declare the package as a "GIFT" or just low ball the declared value. But remember if you or shipper is caught it IS mail fraud.