Siam will be the most visited place for tourist either they stay around there or not. Since it is very well-known for its modern shopping malls, many people are visiting there for shopping. However, if you get out of air-conditioned buildings, there are more choices for shopping.
The area around front of Siam Paragon and Siam Center is called as "Siam Square." Many shops are lined up along the road, and the products of those shops are very nice. Some proven young designers clothes and accessories are selling in the stores, and if you get into a building with narrow street, there are also plenty of shops.
The price is a lot cheaper than the shopping malls, but the quality is sometimes even better than them. Siam square is famous place for Thai youngsters to gather up, and there are also many good restaurants.