I'm another Canadian who has bought over 50 items from the US on ebay and never lost a single package. If I'm not in a rush, I prefer USPS. Small items can be shipped airmail in an International envelope for under $10.00 regardless of weight. Large items like cars and trucks cost typically $15-$30 depending on weight.
If the buyer is in an extreme rush, UPS (Blue) Expedited is more expensive, but no brokerage fees are charged, same with FEDEX.