The government charge is small and set out in the USCIS fee schedule, Form G-1055, for a petition, or collected at the port where a Canadian applies in person. Excluded from that figure is everything the job itself requires: state practice registration, transcripts, background checks and any credential verification an employer demands.
Separate the immigration bill from the employment bill
Applicants tend to research one number and budget for it. In practice two quite different sets of costs run in parallel. The immigration side is inexpensive: a Canadian citizen may apply at a port of entry with the charge collected there, or an employer may file a petition carrying the fee shown in the current schedule, with premium processing available where timing is tight.
Because those amounts are revised periodically, the schedule is the only figure worth relying on. The employment side is where the money goes. Registration or authorization to practise in the state, official transcripts ordered from a university, criminal record and vulnerable sector checks required for school work, professional liability insurance, and any credential verification the employer insists on each carry their own cost and their own waiting period.
Add certified translation where a document is not in English, and travel to a port that turns out to be premature.