Expect to pay at least $1000 on ebay for a nice one but it will still have some "problems" like not having been cleaned so you may not know there could be a crack or two. I know of a $1200 one that was uncleaned, looked great, but had a very fine hairline crack. More like $1800 and up for a really nice one. They come on ebay 3-5 per year it seems though some may be reruns of ones not sold the first time. There is a large web of people looking for good ones so why would anyone sell one cheaply?
I've never had one in my 30 years of collecting but I've seen plenty. Just not that "cheap" one in the pile of dirty skillets at the flea market.
Steve