I've just seen a seller trying to unload an old 500 Zlotych Bank Note from Poland. He is advertising the note as 'valid currency' and exchangable for over $200. While it is true that the note is still redeemable, it's value is certainly not $200. Poland gained it's freedom in 1991 due to the implossion of the USSR.

The Zloty was revalued with the issue of the current series of notes, issued in 1995. The new Zloty is valued at 10,000 old Zloty (1950-1995). The older notes have been removed from circulation and remain redeemable until 2010.

So that 500 Zlotych note is worth $0.021 cents!