At the port of entry the applicant pays the Form I-94 fee to Customs and Border Protection; a petition through USCIS carries the Form I-129 filing fee under the current fee schedule and optional premium processing, paid by the employer.
Two routes, two fee schedules, and the same evidence either way
A Canadian citizen applying for TN at a land border or preclearance location pays a modest I-94 issuance fee to Customs and Border Protection and receives a decision on the spot. If the employer instead files Form I-129 with USCIS, the filing fee is the amount published on the USCIS fee schedule, Form G-1055, for the nonimmigrant worker petition, and employers who want a decision within a guaranteed window can add premium processing at its own published fee. Those USCIS fees are ordinarily paid by the petitioning employer, not the professional.
What the two routes share is the cost of preparing the file: credential evaluation where the degree is foreign or unusual, certified translations, and professional fees if the applicant or employer engages counsel. Renewals follow the same pattern: a new letter and a new admission at the border, or a new petition. Because published fees change, confirm the current figures on the official schedule before the trip or the filing.