I'm pretty sure cels are sold by the animation 
studios in Japan for very low prices, like 5 or 
10 bucks. And fans, collectors, and people that 
buy them to sell them on the internet to the 
people not fortunate to buy them directly from 
Japan. I've seen cels of nadescio floating around 
on very little cels shops , and have seen a few 
floating around on yahoo jp.  I guese that 
Nadesico apperntly isn't that popular for cel 
sites to even bother selling them or the cels are 
hard to find Like evangelion. Also the same can 
be said for Berserk cels Its a very good show but 
the cels are hard to come by like Nadesico.

I don't know if the movie is CG or cels. sorry.