They had to use no money at all to get this trend going. All they had to do was get a few popular YouTubers to show them and their videos and Bam it blew up. The reason is many YouTubers are very popular like Collins Key ,Jake Paul ,Logan Paul and they all use fidget spinners. YouTubers also use fidget Spinners to their advantage they made fidget Spinners with their logo on it and sold them as merch ( Merchandise ). Like if you go to Jake Paul's website you can see that he has a fidget spinner with his logo on it. Many kids think that if they're using a fidget spinner they'll fit in because everyone else has one. I think that if they can learn a trick like spending it on their nose or spending it on their elbow that they'll fit