
There is a significant proportion of scholarships and bursaries (or however you want to define a reduction of fees from 25 to 50%). And the approach differs markedly from school to school.I always presumed that a decent proportion of the "private school" kids drafted were actually public school for a decent chunk of their schooling and then offered sports/footy scholarships during their high school years when it became apparent they were a chance of being drafted. Although I have no evidence to back that up, so could be completely wrong and welcome any confirmation from anyone who knows better.
Schools such as Scotch, Xavier and MGS have full scholarships for Indigenous Australians. All are meant to identify future community leaders, and football is represented strongly, however they also have some in the arts and other disciplines. I am not aware of any non Indigenous on any form of fee reduction, but there maybe cases of football ability allowing a favoured enrolment.
At the other end, Haileybury and St Kevin's have a significant proportion of their 1st XVIII on at least a 25% fee reduction (HC 2018 had 16 of the 22 on some sort of fee reduction). And while they don't offer football scholarships per se; if they didn't have those football skills they normally wouldn't qualify for the General Excellence scholarship.