Government charges are set in the USCIS fee schedule and depend on the employer's size and the forms filed, including any premium-processing request. The larger costs are usually the ones the subsidiary must absorb to support a managerial role: supervisors, payroll and premises that make the organizational chart real.
Budget for the structure, not just the filing
Hypothetical example: the contractor's owner asks for a single number covering the transfer. The government portion is knowable from the fee schedule, which lists the I-129 fee, any fraud-prevention and other statutory fees, and the optional premium-processing charge. What the schedule cannot tell him is whether the subsidiary's current staffing supports a general manager.
If the Washington entity has two installers and no supervisor, the petition will be weak unless the company hires a crew lead and an office administrator before or shortly after filing, and those salaries dwarf the fees. The company should also budget for the Canadian side, because the parent must keep doing business throughout the transfer; drawing its best supervisor into the US operation without a replacement could erode the parent's own evidence. Professional fees for preparing the file, obtaining corporate records and reconciling the manager's travel history are agreed separately.
Relocation costs are a matter of the employment contract.