What he said! With one minor provision. Live sand is *usually* not worth the extra price. it usually costs more than straight aragonite because it's "live" when in reality, most of what is in the sand will have died long before it gets to your shopping cart.
Now, there is always the slim chance that you have a very short supply chain, and it's still somewhat live when you buy it, but the odds of this are very slim. Best bet is just what Sniperhank said. But if you want the "live sand" benthic organisms faster (they'll colonize the sand eventually no matter what you do), you can get a scoop of the top layer of sand from a friend's established tank and gently spread it over your sand.
It's a shortcut, but how useful it really is truly is quite debatable.
Best bet, most economical bet, is to buy base rock and seed with a few pieces of live rock, and just buy cheap sand. The critters that make it "live" will get there sooner or later.