I went to an Anglican girls school in Sydney, fees were $12k in year 7, up to $20k for year 12 not including uniforms, books, excursions, extra curricular sports or other activities.
Per term my parents paid:
Sporting activities: $200 (not including the one off uniform and equipment costs - I played softball, netball, basketball, touch football and did diving so I had to buy softball mitt as well as the appropriate uniform for each sport)
Excursions and incursions: $200 a term
Camps: probably about $500 every year except for year 8
Books: $300 for the years text books plus $100 in stationery over the year
Building fund: $175
Uniforms were about $80/dress (year 7-10), $50 hat, $120 blazer, $75 jumper, $60 vest, $100/skirt (winter 7-10 and all year 11-12), $40 for summer shirts (year 11-12) $50 for winter shirts (different type for 7-10 and 11-12) as well as $10 for the knee high socks and the tie and sports uniforms were at least $50 a piece, so my softball uniform would've been at least $150 with shirt, knickerbockers and the special socks. Regular sports uniform was $30 for the top and $40 for the shorts, $50 for the tracksuit pants and $60 for the track jacket. School swimsuit was $60 and compulsory.
I think the school had a system where each subsequent sibling cost 10% less than the previous one; and if you paid in full at the start of the year you got 20% reduced fees.