I checked for you guys, I got a 310k hp goat. Which is 10k hp more hp then you with being 299k, for a change of 60+ ilvls... which is not too bad, it will still die in 1 shot.
You guy's are thinking to difficult. People are listing them for ~ 100 - 500g on AH, meaning people don't know the value of them, therefore there not people who are equiping ilvl 810, or maxing things before opening.. It's completely random.