There are different levels of live.
here are the levels that I see
Level 1 - Sand that is covered with bactera for denitrification
Level 2 - Sand that is covered with bactera and has small amounts of other life forms like worms or crustations.
Level 3 - Sand that is covered with bactara and contains small worms, starfish and mini crustations
The bagged sand you get in the stores is basicly Level 1 sand. If you go with the marketing on the bag.
Level 2 sand can be acheved with dry sand or level 1 sand and adding some good live rock. The worms, pods
and starfish will have a good chance of hitchiking in on the rock and populate the sand bed over time
Level 3 sand can be acheved with a long time laps with rock and sand or you can jump start this by seeding your sand bed with qualtiy live sand from an established aquairum. lets say an aquarium that hs been up and running for 2+ years.
This is just my take on it.