The fee collected when a Canadian citizen applies in person is modest and is set by the agency taking the application; where the employer files Form I-129 instead, the amounts appear in the USCIS fee schedule, Form G-1055. The larger expenditure is preparation, and the largest of all is a refusal.
Budget for the evidence, and for the possibility of a second attempt
Government charges are the smallest line in this exercise. Around them sit costs a lodge manager will meet whether or not anybody warns her about them: obtaining a transcript from a college she attended two decades ago, having employer letters drafted and signed by people who have since moved on, certified translation of anything not in English, and a review of the offer letter before it is relied upon. Travelling to a preclearance facility on a date that turns out to be premature is money spent for nothing.
A refusal is the genuinely expensive outcome, because it is recorded, it must be disclosed and explained in everything that follows, and correcting the underlying description costs the employer time it never budgeted for. A few hours spent on the duty breakdown in advance is the cheapest part of the whole exercise.