If you google for jobs in Castlegar on kijiji, craigslist, etc., you will see that there are very few jobs there. Which means you may find it difficult in the beginning. But I think there is a city called Nelson close to Castlegar where you can find a wider choice of jobs. If you get a student bus pass, you can work part time at a store in a bigger city close to Castlegar and commute but make sure you do not miss your classes. Just input Castlegar, cities nearby, distance to/from, etc. on Google and check for yourself if you will be able to handle studies and commuting for work.