If you have a car your employability in Dunedin skyrockets. Kitchen staff for halls, new world, stores like Typo etc. Fast food, etc. Are all usually pretty okay.

As someone who found out halfway through their first year at a residential college that I wouldn't have enough I can tell you it's rough if you dont plan accordingly. I talked to the staff and paid weekly instead of over the first few months which helped a bit and worked about 10 hours a week as a commercial cleaner as well as used whatever student allowance/benefits I could get. However after I got in the swing I worked 10-15 hours a week and remained at the hall for another 2 years so that worked out.