I would pay maybe $250 for a good sized one. I dont think its that cool, personally.
I do know a couple folks here have spent well over that for fish or coral. Its all about its worth to you. Some wouldnt pay close, thinking they wouldnt mind having it, but can live without; while there are some out there who would double or triple that if they had to because they just have to have it.
Just my 2¢...