I think Richard sells some of the extras separately, but it's much more economical to buy the package, as the clean up crew, rock, extras are something like wholesale price.
Part 2 of the package consists of 1/2 the rock work, the whole clean up crew and extras.
And here's another reason to get the package...the live rock I got, had almost 15 porcelain crabs hidden in the rock for free...normally $10 a crab.