It all depends on quality I think Al. Your big, flawless fish might push a grand. An 18" xATF in crappy shape woudl probably have a hard time getting $300.
Anyone seriously considering this fish should know just how much work and time goes into getting one of these bad boys big and keeping it in great shape. If you want a fish that's had that kind of work put into it, be ready to pony up! An exceptional fish commands an exceptional price