I'm on Proudmoore, I've seen them average out at about 20k. I've only seen maybe 4 for under 15k and those get bought pretty quickly. As for the Engi pets, they're 15k and up on my server, so it's a fair trade to ask for Pierre or Rascal-Bot for a Moon Moon.
Moon Moons on my server right now range from 13k to 30k+. Just because on your server it's 5k doesn't mean on MY server it's 5k. (For reference I'm on a high pop server, where pet prices tend to be competitive).
I did a solid week long hunt for this pet, stayed up all hours of the day. I would like to say I didn't stay exclusively there, but on the 6th or 7th day I finally found a poor that spawned. By that point I was so fed up with camping him that I decided it wasn't worth the headache of hunting a rare,...
I added you, I'm Amedeesse#1441 I have Whiskers the Rat, Rustberg Gull x2 (one for you and your friend), and maybe a few more that you need. I'm interested in the Air Spirit, the magical crawdad, and viscidus.