The only way to get pure worm castings is to catch it as it exits the tail of the worm. I believe that it would be almost impossible to acquire a cubic yard of pure worm castings. And I'm quite certain that that is why such a price tag was put on a cubic yard of pure worm castings.

worm castings in any quantuty are worth exactly as much as someone will pay .... can't think of anyone who's bought $1300 worth, although if you wet down a cubic yard worth and bag it up in ounce bags you might price it low enough to sell, and high enough to = 1300$ .... as long as it'd take to harvest and bag a yard you wouldn't be making much for your time, even ignoreing tending the worms to produce it

Bill