I've paid anywhere from $225 to $400 for the 
cels I've gotten (a peice).

you'll find they are very rare now as Disney has 
closed down the archive. (its not a rumor. 
you'll find that ANY disney tv cels will be 
significantly harder to find now than a few 
months ago. and even Little Mermaid movie 
cels are harder to find now too)
Any cels you find now are the left overs that 
galleries have (rare to find this), or what 
people are selling from their private galleries.  
Obviously Demona and Goliath are typically 
valuable by comparison. mainly becuase 
people like them.

Though I have NEVER seen an "one episode 
only" type character for sale. (never seen any 
of the different country gargoyles, or the 
scottish flashback gargoyles) I've never seen 
a single shot of Elisa either. she's always with 
someone. I've only seen like one cel of 
Xanatos.

This is my most recent one... 

*very depressed that Gargoyles cels are so 
hard to find now* :(