Oh the Sad, Sad Truth...
I recently decided I would indulge in a Fortune Egg from the marketplace, since I had about 97000 or so gold and I don't get cash because this is only a website -- better to use money on real things.
Anyway, I buy the egg (level 4) for 89500 gold and am only left with about 8000 gold. I try to incubate it to the next level and of course, it doesn't work. It makes me open the egg and look what I get! It's this stupid little 'Oni Set' that is basically a caveman that has about 12 different poses. It looks ugly, to say the least. It turns out I'm not allowed to sell it for a price in the marketplace that'll cancel out my wasted gold, because it's some sort of 'soulbound' item that you can only sell in the actual shops. 13000 gold. I just lost around 76000 gold on a piece of crap.
If you're gonna buy a Fortune Egg, it'd be wiser to sell the egg at an annoyingly high price in the marketplace instead of wasting your time on it otherwise.