All the resorts have shops where you can buy food items and beverages. Usually they're found in the main lobby area or in the main building if you're talking about the Polynesian and Grand Floridian. When we were at WL last week, I noticed that the hard liquor was only for sale behind the register - you had to ask for it. I think I saw beer in the fridge section in the WL store. I don't know if all the resorts have a refrigerated section......I think they do, but I don't know if I saw one or not at the Grand. There's one at the Polynesian and Coronado Springs for sure. Can't remember the others I've stayed at.
Hope this helps a bit.