Hihi

Well, this is one of my favorite series to 
collect cels from :) However, they aren't so easy 
to find. I've seen quite a few of the "normal" 
outfit cels, and they range from reasonable ($50 
and under) to outrageous, depending on the seller 
you buy them from. I've had a lot more luck 
finding BH cels at conventions than online, for 
some reason the online sellers want a lot more 
than the dealers at conventions. Nichibei 
especially has sold me many nice BH cels at 
reasonable prices, as has Anime Chaos. Several 
years ago (3 or 4 now??) I bought some nice cels 
from the-now-Anime-Taro, but they really haven't 
had much of a selection since. Asylum has some 
nice cels for reasonable prices as does Animanga, 
I've found that they update them more frequently 
than anyone else. Mangaya tends to some of the 
rarer transformed outfits, but they also want a 
lot for their cels and I've heard (but never 
experienced) that they can be slow and unreliable.

For eyecatches, opening and closing, 
backgrounded, and oversized cels, be prepared to 
pay mid 3 digits. 

Characters that are easy to find: Big Mama, 
Dotta, Chocolate (normal), Tira (normal), Carrot 
(normal).

Harder to find characters: Gateau, Marron, Tira 
(transformed), Chocolate (transformed), OVA 
cels/outfits

Extremely rare cels: Haz Knights, Milfy 
(especially OVA), Carrot (transformed), Zaha 
Torte, Siryuse (gah do I want one of him ;_; ), 
Eclair, Mrs. Chips, Potato and JiJi, characters 
as children (or SD forms).

I hope that helps. You can find all these cel 
dealers listed here:
http://www-scf.usc.edu/~ckawakam/cels/

take care ^_^
misa