For an authentic shopping experience, be sure to visit the local markets such as Chatuchak Weekend Market and Pratunam Market. These bustling markets offer a wide array of goods, from clothing and accessories to souvenirs and handcrafted items. Don't forget to haggle for the best prices, and be prepared to immerse yourself in the lively atmosphere. Additionally, explore the shopping districts of Siam and Sukhumvit for a mix of high-end boutiques and local shops. Popular souvenirs to bring back include traditional Thai silk products, wooden carvings, and aromatic spices. You can expect to spend around $20-$50 for unique souvenirs and gifts.