I've had a lot of dealing with shipping items from the USA to Canada, and yet I still see people who opt to use UPS Ground and get stung with their horrible brokerage fees. So here's what you can expect to pay.
Only UPS Ground charges for brokerage clearance; it is FREE for all UPS air services (including the inexpensive 3-day option). So take that into account when pricing your shipping - it is often cheaper to ship by air, and you'll get your package faster.
Extra stuff they will charge you on for clearance (even for air shipments):
Bond Fee - 2.7% of duties and taxes, minimum $5.85, if they collect COD at the door. COD Fee - $4.25, for collecting their money at the door.
You can avoid both Bond and COD fees by calling UPS and putting a credit card number down on your shipment before it clears customs. If you ship to a business name UPS will typically call you in advance to ask if you want to use another brokerage firm (businesses often contract all customs clearance out to a single firm - you even could set up an account with one if you wanted). When they call, you can opt to pre-pay your brokerage and avoid those extra charges (although you'll only get an estimate of the fees). Note that they VERY RARELY call if you ship to a personal name, and usually just show up at your door with a huge COD bill (so be pre-emptive and call them).
USPS (postal service) is always the better way to go for ground shipments, with a flat $5 to $8 clearance fee (sometimes they don't even charge). However the faster air mail services are generally more expensive than the lowest UPS Air offerings, so if you need it faster you can use UPS safely if you know what you're doing.
I have also noted that UPS is more likely to charge duty on items (that really should have duty), than Canada Post - I don't think I've ever been charged duty on anything from them.
