This question depends on what kind of alcohol you mean. If you are referring to beer, let’s do the math. A full keg has 6.9 cases, which consist of 24 12oz cans. That would be 288 cans of beer. If you only got one case, that would be 1.92 drinks a person. I would get 4 kegs, so each guest gets 7.68 (almost 8) drinks. For 150 people, it might be easier (and CHEAPER) to make that party BYOB!