DO NOT USE UPS. I was charged $60 in fees for a $100 package
If you send something via USPS, there will be a $5 fee PLUS the person in canada will get charged tax on whatever value you write down on the package (so say it's worth $100...the post office will charge him about $20 before he can even pick up his package). If you mark it as gift he should only get the $5 fee I think, and that may even be waived.
I have no experience with fedex for US-to-Canada shipping.