Possibly even more so at 18 yo. It's a bit of bigotry/racism that seems to only apply to Thais, the Chinese and Indians don't get the same lens applied.
My son went through university about 30 years ago. At the time, he estimated about one-third of the female students were selling sex to help make ends meet.
The immigration lawyer cost me $1100 about 6 years ago. I think the tourist visa itself was $350.
Course fees are dependent on the prestige of the tertiary institution, international students pay more. These are Melbourne University fees:
https://study.unimelb.edu.au/__data/assets/pdf_file/0028/341893/2023-International-Fee-Table_NOV.docx.pdf
Living expenses, no idea. Rents have gone through the roof, I'm glad I am not there anymore.