Just depends, people are honest/ dishonest everywhere. I recommend that you don't leave feedback until there is development. I purchased a dozen eggs that I couldn't find a breeder here. Only 3 developed. I cracked the clears and they had no bullseyes. Most people rate based on arrival of intact eggs. But the only power you have as a buyer on eBay is feedback. You only get one chance. Someone could pack up a dozen eggs from The supermarket and get $30-50, and get a great rating and nothing is even fertilized .
I've gotten poor typed silkies on there and nearly all hatched. In honesty, I was told all her pens were SG to SG and that was obviously not true. But it's not the best idea anyway.
Also, I read on BYC that someone was sold eggs on eBay that turned out to be barnyard mix but were presented as a hard-to-find breed.
Buyer beware.