This is another in the series of "wanted" posters that be found within a campaign setting.
-After looting old ruins characters often find coinage from ancient civilizations. This is an opportunity for the characters to have a ready source for exchanging these coins into readily usable cash. This will draw the characters to a central location after an adventure is over, giving the DM an idea of where the characters will be at certain times. It also allows the DM to threaten this person at a later time and the characters will have a vested interest in saving him.
-However, what is this person doing with all this ancient coinage? Is he a collector on a large scale? Has he found some means to power rituals with relics of ancient times, of which coinage tends to be in the greatest quantity? Is he reselling the coinage to someone he should not be (or can the characters cut out this middle-man)?
-The typical kill-the-evil-monster poster. Simply getting to the target could be an adventure in itself. Also, if it is a powerful monster it likely has followers. This is a good way to allow the players to choose to do a traditional monster hunt. If they decide to follow it up, they are likely letting the DM know that type of adventure is what they are currently in the mood for.