"Radon" or "Radium": a one-time purchase that is lighter than Plutonium

In my opinion, letting non-paying users change their discriminator one-time for free would be a neat compromise. Existing Plutonium subscribers most likely have already customized their discriminator (or have refrained from doing so because of the fear of re-randomization, like me), so their unique identity wouldn't be impacted with that change. Some mobile games (for example Clash of Clans) have the same system: You can change your name for free one-time, but after that, you have to pay for subsequent changes. This is also closely related: Plutonium discriminators re-randomize once it runs out. This holds paying user's discriminator (and therefore established identity) behind a paywall. TL;DR: Non-paying users should be able to change their discriminator only for once and Plutonium discriminators shouldn't re-randomize once it runs out.