Dear God you've got me now!
What's a beer cost in Dusseldorf?
In Sydney, Australia, you can pick them up for $2.60au a schooner (sometimes more, sometimes less), or $1.51 Euro (at current exchange rate 1au=0.58Euro).
Also, in Australia, it's not customary to tip, as our "minimum" wages here are higher, in comparison to many countries, unless of course your barmaid has larger than normal mammaries, or you are desperately trying to get lucky.
You should also note what a tip costs!