Many US sellers use couriers like UPS for domestic deliveries. The service within the USA is fast, tracked, and competitively priced.
However, exports by courier are very different. Be sure that your seller will use USPS/Canada Post for shipping even a bulky item like this.
If you can't find someone who uses USPS, and you are unwilling to pay over $25 for "customs brokerage" on your doorstep, ask if the seller will upgrade you to "priority" shipping.
Although this seems more expensive, it means that duty, brokerage and taxes are covered in the shipping fee. And at a lower cost than the doorstep price.