All you people in Florida should get on the waiting list here:
My Ae Ae's Brother What a super thing. God Bless this person.
I think the price is pretty much determined by whatever someone is willing to pay for it. That's free enterprise, but it doesn't mean that everyone has to pay that price. There are good deals popping up all over the place. My friend found one at a nursery last year for under $50. It was huge in a five-gallon container, and he planted it in the ground, but it died over the winter. Some people here on this forum got some for under $50 at a local nursery last month. The going price locally seems to be $50 even if EBay doesn't reflect that. They are about that same price or cheaper in Florida, and they are even cheaper in Hawaii.
A couple of years ago, people were paying huge amounts for a purple-flowered plumeria. I sent one to a friend a couple of years ago who sold it on EBay for over $400. I just sold one this year for $35. The U.S. market was flooded with them really quickly as people bought and imported them from Thailand, which is the plumeria capital of the world right now. I believe as the supply goes up, the price will come down.