Home Depot sand is safe as long as it is "playsand" with no additives or silicates.
The trick to saving money is put a thick layer of "dead sand" down (at least two to two and a half inches), then buy a small bag of live sand (will cost you around $35). Spread the live sand evenly over the dead sand.
Please remember one thing though. Don't go to Lowes/Home Depot and buy play sand if you don't think it looks nice in the tank. You are going to have your tank for years and years. I guarantee you that 5 years down the road, you will not be looking at a tank you find unattractive and be thinking to yourself, "I'm glad I saved $70 on that sand."
Aragonite looks like kitty litter. It looks a lot better than play sand imo, has water-buffering qualities, and adds over 5 essential trace elements to your water.
For a 55 gallon tank I spent $96 on dead sand and $36 on live sand. It was expensive, but looks great.