Most stuff is brought in by boat, so most things are less original and more expensive than on the mainland. However, there are a few shops that manufacture their goods on the island. Prices for commodities vary widely between shops.
Most of the items sold here are either made by local fishermen or they are brought to the island from Phuket town. Rising commercialization and inflow of tourists throughout the year seems to be a big bonus for these locals. Prices asked may exceed the value of the item, but if you are a good talker, you can bargain for a good price.