The simplest and best description is "What the market will bear". This sounds closer to ShadowAce's clue than yours. His view is also consistent with what happened in Europe when the switch from local currency to the Euro occurred -- businesses used it as cover for large price increases in Germany, Italy, and Greece which did NOT go away.
Exactly and if the market will bear a 30% increase then why is not the price 30% Higher right now?
Do you think the stores competing against the Evil Wal-Mart Empire™ would not jump at a chance to undercut them by using any price advantage they could?
If you and Shadow's assertion are true why then do the price of electronics and computers continue to drop? 6 years ago a state of the art computer loaded with extras from Gateway cost me nearly 3 grand I can buy one with twice the memory and speed and features for half the price now.
Further your example of the Euro has no bearing in this situation. We are not changing currencies we are changing the tax structure. Nice of you to try the old Apples and Oranges trick.