RE: Cross-post: Canadians ordering parts from USA?
USPS is the only way to get stuff across the border unless you want to bend over and let UPS/FedEx/DHL ream you for a so-called brokerage fee. If you're going to be doing a lot of cross-border ordering, it's better (and cheaper) to set up an account with a customs broker.
If you're close to the border, get it UPS'd to a UPS store near the border, cross over and pick it up yourself... much less hassle and still cheaper than the ridiculous brokerage charges the couriers slap on you.
Better still is to buy from a Canadian distributor/dealer. That ensures there's a parts supply in Canada, and probably helps local hobbyists by keeping a bricks-and-mortar store in business.