If you need a license key, purchase directly from the developer’s website (typically $10–$20). For academic or institutional use, check if they offer educational discounts.
You can buy a lifetime license for a one-time fee. folder+colorizer+2+license+key
proved to be "the best 10$ I have spent" for productivity and sanity. If you need a license key, purchase directly
Windows has a native feature to change folder colors without any software. If you need a license key