Specialty stores are usually dried ginseng, which is very expensive. There is a street behind the Olympics, full of shops that buy sea cucumbers. If you eat by yourself, there is no need to buy dry goods.

Go to the cooked food market or seafood market to buy fresh food and shop around. What is fresh is basically true. Dry goods can be faked, and are expensive and opaque. I suggest buying this if you eat it yourself.