I’ve been watching a video game and it’s price on amazon, and the price is slowly going down each day

What causes this? Like, it’s going down a total of a dollar or two a day, but I’ll look and it’ll be one price, then a dollar lower a few hours later. Just never seen this before. It’s still brand new right? Says shipped from amazon.ca via /r/amazon https://ift.tt/2JpYiTt