As it was very warm during the day, the best time to do shopping and also the time when all the shops fully open seem to be in the evening.
What to buy: All kind of stuff sale along the main street of Nang Thong area, Men's and Women's Clothes, Food and Drink, Sporting Goods, Supermarket, Gifts, local craft,...etc
What to pay: Don't forget to do bargain...
There is a small market at Khao Lak (actually a few km away in Bang Niang) that sells food and clothes. There isn't a lot here but the prices are better than the shops in Khao Lak. It is open a few times each week for a couple of hours in the evening. Ask a local for exact details.
Seeing meat sold in 90 degrees of heat with no refrigeration and the vendor using a stick to keep the flies off the meat is an endless source of fascination for me.