Shopping malls and shopping centers. America is the birthplace of the modern enclosed "shopping mall" as well as the open-air "shopping center". In addition, American suburbs have miles and miles of small strip malls, or long rows of small shops with shared parking lots, usually built along a high-capacity road. Large cities still maintain central shopping districts that can be navigated on public transport, but pedestrian-friendly shopping streets are uncommon and usually small.
Outlet centers. The U.S. pioneered the factory outlet store, and in turn, the outlet center, a shopping mall consisting primarily of such stores. Outlet centers are found along major Interstate highways outside of most American cities.
Major retailers. American retailers tend to have some of the longest business hours in the world, with chains like Walmart often featuring stores open 24/7 (24 hours a day, 7 days a week). Department stores and other large retailers are usually open from 10 AM to 9 PM most days, and during the winter holiday season, may stay open as long as 8 AM to 11 PM. The U.S. does not regulate the timing of sales promotions as in other countries. U.S. retailers often announce sales during all major holidays, and also in between for any reason or no reason at all. American retail stores are gigantic compared to retail stores in other countries, and are a shoppers' dream come true.
Garage sales. On weekends, it is not uncommon to find families selling no longer needed household items in their driveway, garage, or yard. If you see a driveway full of stuff on a Saturday, it's likely a garage sale. Check it out; one person's trash may just be your treasure. Bargaining is expected and encouraged.
Flea markets. Flea markets (called "swap meets" in Western states) have dozens if not hundreds of vendors selling all kinds of usually inexpensive merchandise. Some flea markets are highly specialized and aimed at collectors of a particular sort; others just sell all types of items. Again, bargaining is expected.
Auctions. Americans did not invent the auction but may well have perfected it. The fast paced, sing-song cadence of a country auctioneer, selling anything from farm animals to estate furniture, is a special experience, even if you have no intention of buying. In big cities, head to the auction chambers of Christie's or Sotheby's, and watch paintings, antiques and works of art sold in a matter of minutes at prices that go into the millions.