The EQ Economy has had some serious ups and downs over the years, but after the big IGN incident it seemed to have stabilized at a fairly steady rate.
Although in recent years things have inflated a bit more than the usual trend.
(The IGN incident involved a systems administrator level GM who added in an NPC that let you convert currency up and down. Trade 10 copper for 10 silver for 10 gold for 10 plat. Those of you around when Fungus Tunics went from 15-18k to almost 70k in the span of a week were affected by this, though at the time SOE tried to keep it really lowkey).