A dull knife can lead to a dangerous time in the kitchen if you're not careful and slip up. The problem is, good, professionally sharp knives can be hard to come by, because they're always a bit expensive.
JunsKitchen wanted to show you don't need to buy an expensive knife, all you really need is a decent blade sharpener. By taking a $1 knife he purchased from a discount store, and taking it through the sharpening wringer, he made that dollar store knife sharp enoukgh to cut through food, paper, and even water bottles.
The YouTuber used a variety of knife sharpeners that he purchased online. In the video's description, he lists them out for viewers to purchase if they were interested. He sharpens that same knife over and over with the different stones, but eventually, the cheap knife was as sharp as any professional kind of instrument.
He concludes the video by addressing getting some sharpening stones and practicing with the knives at home before trying for the $1 one.
Pretty inspiring to see that you can make the best out of even the cheapest things.