How do you actually obtain the Frozen Tuna?

The super beginner weapon. The Maplestory commercial weapon.

How do you actually get it??

 

Through Gachapon. You can check the thread "Let's play gachapon" to double confirm where you can gach it, but if my memory serves me right, it's from NLC gachapon

 

Are these worth anything? I have a solid amount from days of NLC gach

 

There are two frozen tunas: beginner only and common (all jobs can wear it).

The beginner only one comes from NLC gachapon.
The common one comes from the eraser quest, which you can read about here: https://royals.ms/forum/threads/eraser-quest-guide.128860/
From the guide, the common Frozen Tuna requires:

 

It used to be from gach, you can try find it from FM from somebody who has it I guess
It's not worth to do the quest cause the erasers cost a lot of money since they are being used for the alchemist ring