You might want to find a part-time job while studying in Ottawa, especially if you are living on a low budget. Tutoring Math and its related subjects might be the best option since it is well-paid, non-stressful and quite challenging. However, beware that you must be perfectly fluent in English/French in order to be a good tutor. If you are looking for students to tutor, you might want to post a note on the Department blackboard near the Secretariat, or create a post on Kijiji, which is very easy and convenient. However, if you wish to work for a tutoring school, there are many of them, some of which are:

http://www.ottawamathtutoring.com/

http://www.mathnasium.ca/kanata

I also suggest looking for other job postings on the following links:

https://www.jobpostings.ca/student-jobs/ontario/ottawa

https://www.kijiji.ca/b-part-time-student-jobs/ottawa/c59l1700185

https://ca.indeed.com/Part-Time-Student-jobs-in-Ottawa,-ON

Please keep in mind that you are not allowed to work more than 170 hours per term, regardless of citizenship status. If you want to be fully focused on your studies, working long hours is not the best idea! J