I believe there is a general consensus that live sand in a bag is not "live" sand. At most there may be some live bacteria in that bag but it will not contain any of the other desirable microfauna that most people are looking for when they want live sand.
You should skip paying the extra for prepackaged live sand unless it is collected and shipped directly to you (overnight) from a reputable source.
Instead, either go to a LFS and they will sell you a small quantity of sand/rubble from one of their refugiums that you can use to seed your sandbed or you can try members of your local reef club if you have one in your area. There are usually members that will give you some from either their tanks or refugiums for free or for minimal cost.
BTW, you only need a pound or less. Many folks try to get small quantities of live sand from multiple sources to increase diversity. However, keep in mind that when you accept things from other peoples aquariums (live sand, fish, coral, etc) there is always the possiblity you will introduce something undesirable (disease, pests, etc.). Following a strict quarantine protocol will save you a lot of time, money and frustration.