That still happens now.
When the Ah! My Goddess Movie first came out they 
were selling cels at the opening releases for 
about 17.00 U.S. if memory serves correct.  But 
there was the catch that you did not get to pick 
out the cel you were buying it was randomly given 
to you and I believe there was a limit of one per 
person.

With that in mind and seeing how much they were 
selling for on yahoo Japan when the movie first 
came out shows that cels will not stay at that low 
price for long if there is a big enough fan base 
behind it.