A PhD worth getting should not involve you paying tuition. Much of the time your tuition is waived and you earn a small stipend (just enough to live frugally off of) teaching/working in a lab.

From a university's perspective, grad students are cheap labor that can eat a lot of sections of low level undergrad classes.

It's expected that your supervisor pays your tuition because he has grants. This is important signalling. No stipends means no grants and a worthless program.