My guess is that the prices will not come down.
Simply because Ghibli has not released the cels
and most likely will not. The ones you are seeing
somehow got into market through different
channels (I'm no expert on this). So you won't
all of a sudden see a bunch more cels and with
the demand the way it is....
I suggest you save up if you want one. That's the
only way ^^ Good luck!