Gizmo hit another nail bang on the head when she said that nothing will become cheaper by changing the currency.

A friend of mine in Germany told me, that when the Germans went from Deutschmark to Euro, prices went up by at least 10%, ostensibly to cover the cost of changing all the tills, vending machines and what have you from handling the old Marks to handling the new coinage.

Only, prices were never seen to come back down again to the previous level, although one must assume that this conversion can't really have been a perpetual cost, but must be assumed to have been over after a limited duration.