Purchase from Canada

State tax plus possible duty and brokerage would apply.

Your best bet would be to pony up for the fastest rate of shipping which in my experience nets you the lowest fees and also minimizes the chances of shipping damage.  

Have the seller mark the item clearly as used will help.  Undervalue at your own risk, I've done it but again only with the fastest shipping option being used.

I have bought from Canada on several occasions from interconnects to a Consonance Droplet 5.0 cdp at about 60 lbs to a pair of Xindak monoblocks at about 50 lbs each.  I was hit with customs on the interconnects only and that was through UPS.  When I shipped via Canada Post, no customs were charged.   

@lcherepkai  same here. Shipping via Canada Post no Duties paid but can take 7-21 days to arrive. Shipped via FedEx or UPS Duties always collected.

I've both shipped and received audio to and from Canada, so many variables. Small items via Canada Post, USPS, no duty. UPS and Fedex, yes there are duty charges, duty charges variable depending on duty codes. Used or new matters, can adjust declared used price to whatever buyer and seller feel comfortable with, be advised this could cause issues. I've not had any thus far. Fedex and UPS have guaranteed shipping dates, USPS and Canada Post can be problematic, therefore, occasionally sit in customs for many days.

One thing to be aware of with Canada Post.  They have no ability to track your shipment once it crosses into the U.S.  You can pay extra for tracking but............