Kamala has some small minimarkets, including a 7-Eleven. There are quite a few souvenir shops on the road, along with some tour offices where you can book lots of different tours for diving or beach watching.
Most noticeable are about 20 to 30 tailors (including two just outside the Kamala Bay Garden Resort), which all try to guess your nationality and offer the "best and cheapest suits in Western fashion". Before entering one of them, you should be well aware what you want and what you are willing to pay for it. Upon delivery, you should check all the seams.