Being a poor university student I have to mostly settle for the cheap beers I can get in the local supermarket unfortunately, of those I think Sternburg and Wicküler/Wickueler give you the most bang for your buck.
Though I probably shouldn't complain, from what I've heard beer is pretty damn cheap here, compared to other countries. :D
i would say oettinger is cheaper, or the pet beers from aldi/lidl/penny...
and they arnt so bad compared with the most midrange beer outside of germany