Honestly I see no point doing Dr Du unless you go to Ruse or you want a really competitive environment. Some of the questions there are copied form UNSW worksheets and at times they can be a little random such as learning the cross product or doing uni type Qs but one thing that can be said is that you'll be very ahead of your peers.
I just don't see a reason to break the bank, 1.2-3k per term I believe, for this since you can utilise online resources to kickstart yourself however this opinion holds no weight since I haven't tried it out. If I'd want a tutor I'd go for private since at times its more cheaper as well as you'll be able to receive more attention and help since its small classes or it could be one-to-one.
Self study is a great skill and I'd highly suggest people try studying themself for a bit but if you need a tutor there's no shame in rolling out the bucks esp. if your parents can afford it and they think its the best for you.
Anyways in university its all self-study. Its a hail mary if you get a decent or good professor but you'll find most lectures are not the same quality as say online videos or study notes.
If you're solely dependent on tutoring for your studies, I wish you all the best when you rock up to university and you're expected to learn all of 4U and more in 10 weeks by yourself with little to no guidance. Lectures are very bare-bones and designed in a way such that you can only complete very basic to low intermediate questions, to get harder questions you really have to have a strong grasp on a subject and be comfortable with going outside the course.
Literally for COMP1511 (Intro to programming), we had one of the worst lecturers I've ever seen. The sound quality was extremely poor and the camera tracking was awful to a point you were better off taking a 2hr nap than try to learn. He was also always going on about other courses than teaching the course and he was so dull I STOPPED watching lectures all together after that. My tutor literally warned this guy was shoddy and I followed his advice to study off the internet and I copped a 99 on my first assignment with no lectures for 1 week straight.
I've basically only watched the first 3 week lectures for all my courses and the rest has been pure self study. Way more effective. Less time consuming.