If someone has a maxed rare pet, then I'm pretty sure they would have much more than 1 character slot or vault. Also, there aren't many people who actually max rare pets on unnamed accounts. If you can manage to find someone who has only 1 char slot and vault with a maxed rare, it should go for 40-50. You'd be hard pressed to find someone who would lower their price to 50$ if they have multiple character slots. Good luck with this.