Like the previous posters:  it totally depends on 
the scene and the quality of the shot.  I've seen 
head shots of SM that I wouldn't pay $50 for, and 
then I've seen head shots that I'd pay $500 for.  
Cels of Sailor Moon tend to be more expensive 
from different seasons, I think.  Also, is it an 
end cel?  Bank?  Does it come with a background 
(matching or non-matching)?  Is it stuck to a 
sketch?

If you can make the picture available or give a 
more detailed description, some of us here might 
be able to help you out more.  Either way, good 
luck with it!

~Anne