Well, cels of Folken can get quite expensive...  
I've seen anywhere from $50 to (in a couple of 
cases) $1400.  But you're more likely to see them 
in the $75 to $500 range.  Unfortunately, I've yet 
to find a cel of Folken that I love that much to 
spend that kind of $$ on.  (Especially when I have 
so many other animes seducing me into buying cels.)  
;-)

Dilandau's not quite so much.  I've seen anywhere 
from $20 to $350.  

But, of course, this all depends on the dealer and 
the cel/pose/scene depicted.

Hope this helps some.  I'd say just keep your eyes 
open.  Trust me, bargains can be found.  :-)

--Kris
....