There are too many factors that you have to account for...
I think that just asking "how much?" is too vague.
Like someone from place "x" may pay in the hundreds because they it may be a fish that is rare.
Or you can have someone from place "y" who would pay half that because his lfs has flowerhorns coming in all the time at decent prices. you know.
If you know what kind of fh it is that would be better. I paid 40$ for my fh and he is about the same quality. Granted he may have been smaller than that one.