At the port of entry there is an admission fee for TN and an I-94 fee, both listed on official schedules; a USCIS petition instead carries the Form I-129 fees on the G-1055 schedule. Other costs may include credential verification and any state licensing the employer requires.
Match the fee to the route you actually choose
Do not budget from a friend’s experience; the fee depends on the process. If she applies at the border, the relevant charges are the TN application fee and the Form I-94 fee collected by CBP, and the current amounts should be read from the official fee pages on the day of travel. If the employer prefers Form I-129 with USCIS, the filing fee and any asylum program fee are on Form G-1055, and premium processing is an optional extra.
Beyond government fees, expect to pay for a licence verification letter from the provincial regulator, courier costs for originals and, if the degree is from outside Canada, Mexico or the United States, a credential evaluation. Some employers require a state forester licence or registration before the professional signs plans; that is a state practice rule separate from TN and may involve examinations and its own fees. Ask the employer in writing which costs it will reimburse, because reimbursement policies vary and are not part of the immigration analysis.