Items over $20 might be subject to tax (like our sales tax)--if you ship via USPS it's hit or miss as to whether the package will get stopped or not. If you ship FedEx or UPS the buyer will definitely be billed for tax if the item is over $20. There's also brokerage fees--FedEx usually includes it in their online price quote (which is why a package under a pound is like $50 to ship), UPS will surprise your buyer with the fee if you send it ground but will include it if you ship one of the faster services:
UPS
http://www.ups.com/content/ca/en/shipping/cost/zones/customs_clearance.htmlFedEx
http://www.fedex.com/ca_english/international/customsservices/index.htmlIt's not unusual for a First Class Mail package to Canada to take 3 weeks to arrive, if it gets stopped by customs it might take longer.
You need to include a customs form, see here for help printing out a First Class Mail label with the customs form right on it:
~~Shipping Basics~~
http://www.etsy.com/teams/7722/business-topics/discuss/6382394There's also info on third party insurance if you need it--USPS doesn't offer insurance for International First Class nor the small flat rate International Prioirty box or envelope.
Most international buyers know it will cost more to ship, take longer to arrive and that their might be taxes due--don't let those things keep you from selling to the rest of the world. :)