If that Caribbean is the same as I got a few years back it is dense and heavy. Mine had a lot of life on it, clams, sponges and even a gorgonian. But that price is ridiculous, IMO. For what you would likely end up paying for that rock, you could probably buy a small amount of
aquacultured rock such as tampabaysaltwater or waltsmith if you are looking for rock with a lot of life on it. Otherwise, just look for the cheapest 'fresh' rock you can get, cured or uncured if you are willing to cure it yourself.