I lived in Plainville for 6 years, and I comparison shop for everything, including wine and beer. Plainvlle Liquors has the lowest prices in Plainville and most of North Attleboro. The item that I bought most often here only went up 50 cents in the 6 years I lived in Plainville. They have excellent selection; staff is extremely helpful, and knowledgeable. The staff has remained the same over the 6 years I lived there - I believe they are all the owners.
Pros: Low prices; excellent selection; very knowledgeable and helpful staff.
Cons: There isn't a chain.