Actually the great deal of cash depends on the nation you want to change to, or more specifically the where the nation is ranked.
I know to change to the number one nation is around 40,000. I think number two is around 10k-15k (might be 12 but it's been a while since I checked). And the third ranked nation is 4k-7k if I remember right (but I could be wrong).
Edited, Tue Jan 27 11:37:34 2004 by Jigensan