Any idea on it's worth?

a mottled parchment envelope riddled with mold

You analyze your parchment envelope and sense that the item is largely free from merchant alteration restrictions.

The creator has also provided the following information:
This item is a box to store multiple labels.
A merchant can alter this item with a long description or a show, but it must remain some kind of small, unwearable container.
It currently contains 50 labels out of a maximum of 50.
Certain merchants may be able to deepen this item to hold more labels.
This envelope is unlocked; it will automatically unlock your label when you pull them out. Additionally, this envelope supports TILT, TOUCH, and KNOCK.

I dug up an old post from November of 2012 of someone trying to sell a box of 40 labels for 2million MB, but that seems kind of high to me for what they are. Is it accurate?