You are right, this isn't in the right category. I will move it.
To become a cavy slave, you must have been a member for 30 days and have I believe at least 10 posts. To become a Cavy Star or Cavy Champion, you donate. To become a star it's a donation of at least $10 per year and to become a champion, it's $10 per month. There is a big thing on the left side of the main forum area
http://www.guineapigcages.com/forum about Cavy Star's.
To see all the ranks there are- look at the bottom of the page I linked and see the Legend.