For those coming from out of state: In Philadelphia, you cannot buy alcohol at the grocery store and you have to go to specific stores depending upon what you want.
For wine and liquor, you should find a state Wine & Spirits store.
49th and Baltimore
24th and South
Many more in Center City
For a case of beer, go to a beer distributor.
University City Beverage – 4300 Walnut
For a six pack of beer, any local pizza place will serve. The one on 43rd between Locust and Walnut has a good selection.