The shrewdest and longest
advertising ploy in
world history. Plays off the fact that the human
brain interprets 99 cents as being significantly less than one
dollar, and it's been proven that vendors can lower their prices by that one
penny and show a
statistically significant increase in
demand.
Gas stations take this to a high new level, as that "9" in the
corner of the
price on the
billboard that no one seems to know the meaning of actually means nine-tenths of a penny.