Daniela VILLARREAL
Very affordable
I recommend you to stay in Oaxaca Casa de Don Pablo hostel, with its excellent quality-price ratio. In fact, the rooms are very good, with a friendly staff, and the hostel is fairly close to the city center. For about €8 a night, including breakfast, you'll have a pleasant stay in the Casa de Don Pablo. After you have done some research on the Internet, I think this hostel is the cheapest option.