Where a petition is filed for the adoption of a child who has been placed for adoption by a county adoption agency, licensed county adoption agency, or the department, the county adoption agency, licensed adoption agency, or department may, at the time of filing a favorable report with the court, require the petitioners to pay to the agency, as agent of the state, or to the
department, a fee of five hundred dollars ($500). The
county adoption agency, licensed adoption agency, or department may defer, waive, or reduce the fee if its payment would cause economic hardship to the prospective adoptive parents detrimental to the welfare of the adopted child, if the child has been in the foster care of the prospective adoptive parents for at least one year, or if necessary for the placement of a special-needs child.