The government charge is small and published in the USCIS fee schedule, Form G-1055, whether the employer petitions on Form I-129 or the applicant is processed at a port of entry. The larger costs are credential evaluation, certified translation, employer time, and a second attempt after a refusal.
Budget for the evidence, not the filing
Hypothetical example: Odile trained in graphic design in France before settling in East Ferris and taking Canadian citizenship, and an American publisher has offered her a staff design role. Graphic Designer is an Appendix 2 profession, met by a baccalaureate degree or by a post-secondary diploma or certificate plus three years of experience. Her French diploma is where the money goes.
An evaluation from a recognized credential service, a complete certified translation of anything not in English, and replacement transcripts ordered from an institution abroad are all real expenses, and they take weeks rather than days. Around them sit costs nobody budgets: the employer's counsel reviewing the letter, a drive to a port that turns out to be premature, and the compounding cost of a refusal, which every later application has to answer for. Check Form G-1055 for the current government amounts rather than a figure quoted in conversation, because the schedule is revised from time to time.