Red Bull used to be available at certain bars at Roppongi but they used to cost a fortune. Not anymore. Just go during happy hours at Senta-gai Gas Panic and you'll score yourself Red Bull Vodka for only 400 yen. Aint too shabby when I used to see the same drink for 1400 in Pongi! Only if they had Jaggermeister at GP, then I'd cream a load.
