the other thing to look at is this... you may be looking at below 4 dollars a lb. but what are you going to have to do to the rock before you can put it in your tank...
clean it, cure it and then put it in totally dead.
I am with Lando, look at LR
.com... they are a dollar or two more per lb. but typically have next to no die off, and it comes with tons of life.
75g w/ 30g sump, 160# LR
, 60# sand: Inverts =18 turbos, 30 nassirus's, 40 blue leg's, 5 emeralds, 1 CBS, 1 skunk cleaner, 1 brown gulf shrimp? and various other LR
hitch hikers yet un discovered or un-ID
Fish=1 yellow tang, 1 yellow headed jawfish, 1 pink/blue shrimpgoby, 2 perc clowns.
Future fish = 1 sixline, 1 lawnmower blenny