On the main street that leads to the famous Bridge on the River Kwai and on the same street where the Jeath War Museum is find countless shops of all kinds. You can buy clothes, accessories, food ... But mostly they are antique shops and jewelers. This is a very popular place as there are several attractions around, so it's no surprise that around here many businesses have opened. It's the same in almost all of Thailand. There are also many branches of international banks so you never run out of money to buy things.
Given that Ao Phra Nang is a rather indespensable step for hitting the other beaches in the area, it's not a surprise that is is the most commercial zone in Krabi. Ao Phra Nang is an easy place to spend the summer as it is equipped with all the amenities of a beach resort. One of the main streets, Ao Nang Soi 17 is the perfect place to refuel. There you can find Clothing of all kinds, accessories, jewelry, massage, beach accessories, bars and restaurants, etc. It's all well organized so that your purchases are easy and you must remember that this is not your last destination as there are other beaches to see such as Tonsai, Railey, etc.. You should buy what you need here because you might find other spots more desolate. In any case you can always rent a boat back if you forget something. If, however, the final destination is Ao Phra Nang you won't have to worry about anything as there, you have all that you need. Prices are similar to those of the rest of Thailand and as it is a beach area, it is very economical for a Westerner. You can find perfect jeans for 8 euros or 6 shirts, beach flip flops for 2 or 3 euros, one hour massages for $ 5, and more.
Close to one of the restaurants in this bay you will find stores where you can buy a bit of everything. From clothes to all types of souvenirs like T-shirts with motifs that are typical of Thailand, sandals and flip flops, sarongs, towels, sun lotion, decorations, rolls of film or memory cards, cameras made for the water to take pictures, hats, etc ..... These shops are well equipped and organized. Usually part of some other business like hotels and restaurants are in separate enclosures in the beach sand. It is not necessary to go to a hotel and cross the entire complex or through a restaurant to buy anything. You know that even being on an island in the ocean you will be missing nothing. This is general throughout Thailand.