NOTE: Treasure Hunter quests may not be enabled on your server. Some Ragnarok Online private servers choose to disable or customize the THQ quests.
Treasure Hunter quests (sometimes known as THQs or Token Quests) are repeatable quests that when completed yeild tokens as rewards.
These tokens can be exchanged for rewards such as weapons and cards at the Token Shop. Your tokens are shared among all of the characters on your account.
To become a Treasure Hunter and start earning tokens you must enroll on the second floor of the Treasure Hunter Guild in Yuno. The building is in the lower left corner of Yuno (the first NPCs you will see once inside will be a Kafra and a 'Pub Master'). Go up the stairs to the second floor and talk to the Guild Master at the end of the hallway. Pay him 25,000z to enroll as a Treasure Hunter and start completing Treasure Hunter Quests. You can only complete 1 quest every hour, and a quests' availability resets each server hour. This means that if you complete a quest at 1:57, you can do another one at 2:00. So time your quests carefully so you can do 2 quests right after each other.
NOTE: Easy quests are in Blue and hard quests are in Red. Harder quests give more tokens as a reward.