The cost of living in Freiburg im Breisgau is not that high, taking into consideration the everyday life costs, supermarket, food, etc.
What it varies though is the rent. Because of the high demand and the difficulty to find an apartment, but also a room, the rent is round to 500-600Euros per month.
If you are a student, I would suggest you to contact the International Office of the University in order to get some offers for a student dormitory (ca 300-350Euros per month).
The minimum wage is 9,19 Euro/hour, so you can compare with the job offers you get, if it is sufficient for you or not.