Most of these hardware stores likely have plenty of shovels out in the back. During snowstorms, they like to create "artificial scarcity" of these items so they can jack up the prices. Since you think you are getting one of the last ones, you tend to scoop it up and pay the higher price without even thinking about it. Even if you already have six or seven shovels in your garage back home.
Road salt and car snow brushes are other examples.