I had to replace my copy back about 01-02 when I lost track of the friend who borrowed it- it was $20 at Gamestop then, black label copy.
I don't think the prices are terribly unreasonable now... RPGs typically command a higher resale value later anyway, some of those 10 millions copies have certainly been destroyed along that, combined with what I call 'mental inflation'- the spike around Advent Children put everyone in the mindset that the game is valuable. So, even though there's plently around, people are charging more 'becuase it's rarez', and people are willing to spend more 'becuase it's rarez'. Basically, it's idiocy raising prices.