You can always negotiate any fees imposed. Ask for a breakdown on the costs. And consider narrowing your request in order to reduce fees. While federal agencies are supposed to respond within 30 days, that response is often limited to a short note recognizing your request. Extensions are frequent and it can take months to access some information.
Response times vary from department to department.
Be sure to call the FOI administrator occasionally to check-up on the progress of your request. And if things are getting out of hand, complain forcefully. If the stone wall is high, your best recourse is taking your complaint to the federal or provincial information commissioner. They can look into cases where information has been denied or unreasonably delayed and attempt to pressure bureaucrats to release records. But information commissioners in Canada can't compel government departments to provide access to records.