The Oktober fest beer is brewed to a "slightly" weaker ABV and natuarally a higher price.
The Hofbrau House is recommended and is not a rip off ( but I was not here for Oktober fest) Also look out for the Paulaner brew bouse - much smaller tha HBH lots of copper etc etc ( its a brew house!! ) probably also a few more brew houses to look out for. Munich is dead easy to travle around by the U-Bahn / buses just buy a day ticket.
There is also a "house of hundreds of beers" or something like that - sells bottles from all round the world but is VVV expensive