The government charge collected at the port of entry is small, and where an employer petitions instead, the fee is the one published in the USCIS fee schedule, Form G-1055. The larger spending sits around the application: credential documents, regulator letters, translations, advice and the trip itself.
The fee is the cheapest part of the exercise
Because a Canadian citizen may apply in person and needs no visa stamp, the moment of decision is inexpensive. Budget honestly for everything else. A letter of good standing carries a regulator's fee.
Ordering a replacement parchment or a sealed transcript takes weeks and money. A credential evaluation, if obtained, costs more than either. Certified translation is charged by the page and must cover the whole document rather than the useful part.
A review of the employer's letter before travel is the single most cost-effective item on the list, because it is far cheaper than the alternative. That alternative is a refusal, which costs the trip, the delay to the start date, and something harder to price: every subsequent application will be answered against it, and the second attempt has to explain the first.