It has a great reward: Your very first Monograph

The Monographs are special items in the bazaar, which make monsters drop rarer loot. Not gotten by selling different kinds of loot, they are aquired by fulfilling certain conditions.


Hunter's Monograph
Affects Beasts and Avions. To get it, complete the Thextera hunt, then speak to the merchant Gatsly. It costs 18,000 gil though so you may have to wait till Lhusu mines to get it

The others are priced around 18-22 thousand gil too:

Knight's Monograph
Giants and Insects, Talk to the owner of a weapons shop 30 times

Mage's Monograph
Fiends, Talk to the owner of a magick shop 25 times

Dragoon's Monograph
Dragons and Plants, Check the hunt board 40 times

Sage's Monograph
Elements, Talk to the owner of any shop 100 times

Warmage's Monograph
Amorphs and Undead, Check the hunt board 20 times

Scholar's Monograph
Constructs , Talk to the owner of an armour shop 15 times