Chatuchak market.
The weekend market is something of a Bangkok institution. It has a reputation for having just about everything you can imagine on sale (which it deserves) at cheap prices (a reputation it doesn't necessarily deserve). The market is near the northern edge of Bangkok, but thanks to the subway opened in 2004, it is very accessible to visitors. The Kampangphet subway ('Metro') station has one exit right inside the market.
Satellite image from Google Earth.
The market has been expanded a couple of times in the more than 20 years it's been at its current location. The original market is a reversed "L" shape. Stalls consist of one or two spaces about three meters (10 feet) square. The stalls and the narrow aisles between them are covered, but mostly not enclosed and air conditioned, so shopping here can be a rather hot affair (see JJ Mall below).
A large center courtyard runs down the center of the "L", with a clock tower in the center. The old portion is surrounded by what once was the parking area, but cars have now been banned from the market, making it quite a bit cooler than it once was. Electric carts now provide free transportation around the market.
Souvenirs on sale at the market.
The market is ostensibly divided into "zones" for specific types of items, but these are not at all rigidly enforced. You'll find clothing in the home decor section, and decorative items in all other sections.
Many visitors, using old maps, completely miss the newer sections, officially known as "Chatuchak Plaza". The aisles are considerably wider in this area, which makes it much cooler than the old market. The new section is mostly devoted to decorative items such as lamps, fountains and wood carvings. North of this section is a large market selling tropical fish and all the associated equipment needed for a home aquarium.
As the name implies, Chatuchak Weekend Market is open on Saturday and Sunday, only. Hours are basically sunrise to sunset, but most shops don't open until around 10:00.
JJ Mall
In early 2007, the first fully air-conditioned mall opened at the Chatuchak market. Although air-conditioned, the new mall maintains the market atmosphere, with small stalls selling a wide range of goods. The building is deceptively large, since more than half of it is for parking. The mall itself covers just three floors. Since it's air conditioned, shopping here is quite a bit cooler than in the main market. Added amenities include several restaurants and a large food court. One last added feature is that the mall is open every day from 10:00 to 21:00.
Farmers Market
Across the busy Kampangphet Road from the weekend market is the Farmers Market, a fresh market operated by the Agriculture Ministry. The displays of fresh fruits and vegetables are quite eye-catching, making the market a great place for foodies and photographers. It is best reached from Chatuchak by walking through the Subway station.