Something to keep in mind. Not all Home Depots carry the same play sand. On the east coast, some HDs get (or I should say used to get, since I don't know what's going on today) aragonite based play sand, often referred to as Southdown or YardRight. This stuff never made it to stores on the west coast, which makes sense as shipping sand is expensive. Several years ago, people were pooling together funds to purchase pallets of the stuff and bring it west.
My guess is that since you're on the west coast, you won't see aragonite based play sand. Then you will need to determine if silica based sand is worth the risk. Personally -- chemistry aside -- I chose to remove that whole equation by getting commercially available reef-safe sand. I just didn't want to deal with it, in case I had a problem with the tank and didn't know what to attribute it to. I didn't want to possibly blame the sand I was using and then think I'd need to remove it from my tank.
Long story short, do what you think you can handle -- you may end up saving money but worry that the sand you're using may be causing problems in your tank. Or, you may not blame the sand at all, then everything will be good.