I got the rock and sand from Reef Rocks and it was $100 for 40lbs of rock and 80lbs of sand shipped. It was actually too much sand, I have about 15 or so lbs left. Not going to find it much cheaper than that. Really nice rock too, the same stuff Ultra Corals sells.
The other good thing I forgot to mention is that if you email him prior to ordering, he will include shelves or he will cut the bottom of some rock flat for base rock. I bothered him a lot when I got mine and he was great to deal with.
Petsmart has Carribsea live aragonite sand on sale for the best price I have ever seen. I recommend sugar fine grain size as the larger u go uneaten food and detritus will eventually work it's way into your sand bed and cause all kinds of problems. As for rock go to bulkreefsupply.com and get dry reef saver rock! It's like 2.10 a pound, free of algea and critters, and good for the enviroment. Hope this helps