There are hundreds of bargains to be found while shopping in Koh Samui. While almost every corner of the island has a store worth visiting, the main shopping sites are in Chaweng, Lamai and Nathon. Chaweng offers the most choice and Lamai has a nice range of quirky little stores, but Nathon usually has the cheapest deals.
Thailand is famous for its dubious copies of almost everything, from watches to trainers to CDs, and Koh Samui shopping is no exception. Such products can generally be found in the smaller local markets. Most department stores offer only genuine products and have fixed prices, but you can bargain almost everywhere else. Just keep it polite and friendly to reach a price everyone is happy with.