First of all the idea is taken from Linus Tech Tips forum. They offer three paid subscription badges bronze, silver and gold. All of these subscriptions also offer certain privileges but in Discourse we earn privileges rather than buying which is perfect.
Now, what I am saying is that I liked the idea of buying badges rather than privileges. Can we have a way for members to buy certain badges which they can show with their user avatars (like flair) for a certain period? Like one could buy a badge for $5 for a year and after the year is complete he get a notification that he needs to renew his badge.
Although, while typing I also got an idea of paid groups? This is a rough idea but it can work pretty well if brainstormed well with all the community members here. And this can also provide one monetary help for website owners.