150 ppl...Hah that need a lot of money to spend :P
Buy like...300-400 beers and 5-6 5L Heineken's
About vodka...Buy like 30 absolut vodka and some lemon/orange juice
Also buy some Usrus.15-20 bottles.
For food buy something that it is easy to eat.Like club sandwitch,chicken bites,chips etc etc
OFC you have to make a bar.Pay 5 people to server the others cause it is going to be a mess with 150 ppl.
Gl and happy birthday! :)