Dark Water skins have a chrome-coated base and are adorned with gray wavy lines, giving the impression of dark, murky waters. The skins were added into the game at different times and in different updates, and as a result, can be obtained from different csgo cases. This skin group currently has four skins in its collection and come in two exteriors, Minimal Wear and Field Tested and they all have the option of adding StatTrak to them.
As for the price, they vary from $1 to $90, depending on the exterior.
Check out other CS:GO skins families: