The government charge is modest and is set out in the USCIS fee schedule, Form G-1055, for an employer petition, or collected at the port of entry for an in-person application. The larger costs are preparation, credential documents, certified translation, and the repeat attempt that follows a refused first try.
Budget for the paperwork around the fee, not the fee
Presenting in person is inexpensive at the moment of decision, and a petition filed on Form I-129 carries the USCIS fee, with premium processing available where an employer wants speed. Because those amounts change periodically, Form G-1055 is the only figure worth relying on rather than a number quoted in conversation. Around them sit costs nobody budgets.
Ordering a parchment and a sealed transcript takes time and money. A complete certified translation of French documents is required, not optional. A legal review of an offered equity stake is money well spent before travel rather than after refusal.
Hypothetical example: a forester from the area is told the employer will reimburse everything after ninety days of employment, and he books travel before the letter is finalised; when the letter arrives describing duties he had not agreed to, the trip is wasted and nothing is reimbursed. A refusal recorded because a document did not match the job is the one expense that appears on no fee schedule and follows every later application.