Do you have to be 18 years or older to buy a power tool online?

I want to buy a RYOBI 4.5 Inch Angle Grinder because I love building things out of metal. I'm planning on buying one from the Home Depot website with a Visa Gift Card. But before I buy it, I want to know if it's illegal for a minor to buy one over the internet? Or if they'll ask for parental consent?