Blue Medallion

The Blue Medallions are part of a main game Minigame in Resident Evil 4. You first get this assignment by seeing the note pinned up on a tree in the farm, right below a blue medallion. When you reach the second Merchant, he asks you if you have seen the Blue Medallions and that if you shoot ten, he'll give you a specialized gun. If you shoot all fifteen, he will give you a free upgrade. This is a hint on why the Merchant did not join the Los Illuminados as he encourages Leon to shoot the medallions which have the Los Illuminados insignia etched in it.