Yes, I think the tipps from others about nearby towns are very good, and most FeWo-type places would be well out-of-budget for students, so you are not in direct competition with them, of course. But nevertheless, it really is worth planning ahead on this, because even though Freiburg is not a huge "large city" in Germany, the rental market is really wild and very, very tight, especially at the start of the semesters in October and April. It is also the fifth-most-expensive large city in the country! (See here).