Strict control. OK, in my state, Beer, wine and liquor is bought at a licensed retailer. We call them Package Stores because everything must be put into a package ("packy" for short). No supermarkets or convenience stores. MUST be 21 years of age with ID. 8am to 11 pm Monday - Saturday, noon -11pm Sunday. A store wouldn't risk selling to an intoxicated person or under-age because they lose their license. Some towns are dry (nothing in stores or restaurants, no bars). No drinking in public (parks, beaches, buses, streets, etc).
Varies by state except the 21 years old part. Jack Daniels whiskey is made in a dry county. Some states still have drive-through liquor stores.