It's nice to have a short, memorable URL that you can easily paste in your email, share with friends and family, and have printed on physical media. That's why we created /buy, which is a durable URL that instantly spins up a new checkout link for your preferred paid subscribers who go through this URL. They will automatically be marked as a premium subscriber, even if they haven't already subscribed to your newsletter. It's a great path to streamline your initial launch.
You don't have to do anything special to use /buy (besides set up paid subscriptions): it's just buttondown.com/yourusername/buy.