I'm not sure this is possible in a retail setting. There are rules around incentivizing the purchase of alcohol. Which is why you don't see promotions like buy one get one free... with the exception of happy hour and bottomless brunch sort of deals. Which have a whole different set of rules and exceptions.

I'm sure there are several services out there that send you a monthly amount of beers, preferably different kinds and whatnot. If not, that needs to be a thing, :D.