The price of rent largely depends on your location, whether you have roommates or not, the quality of the housing/apartment and whether you have your own bathroom or not. You can go cheap, like $500 but you'll probably have like 4-5 roommates sharing most of the space.
So none of your friends were able to get any jobs at all afterwards? Not even in the places where they did their practicums? Also how many friends are these that did the MPH?
Is your friend working in the MPH field now? If so, is the job atmosphere and pay enough to justify the expense?