My PhD (in Canada) was fully funded by the university for a set period of time...I think it was 5 years, but we could apply for extra funding if we didn't finish after 5 years, so really I think the limit was 7 years. We also had to do other jobs for the university, either teaching or research assistants. But the idea was that as a PhD student, we were actually employees of the university, so full funding was sort of the equivalent of a salary.

I'm not sure if it works that way at every university, but I've definitely heard that in the UK a PhD isn't always automatically funded. Whenever people in the UK ask about this, the answer is always "absolutely do not start a PhD if it's not fully funded". You should be compensated for your labour, and that includes your research! A university will benefit from your presence and your work, both now and in the future, and if they aren't willing to fund you then you shouldn't go there.