Here's a link to some pretty inexpensive stuff, but it's still only dollars less than the Live sand. With "Live" sand, it's the bacteria that you're after (not dead), and it is very beneficial to a new tank set-up. But for someone with existing tanks, it's just as easy to buy dry sand and toss in a couple of cups from one of your other tanks to seed it.
Home Depot/Lowes sand/Playsand contain harmful silicates.....Unless it's some kind of a deal going on, I don't think you'll get much cheaper than this:
http://www.thatpetplace.com/meridian-oolitic-aragonite-substrate-19lb