Vial

Vial is a free-to-play item on the OSRS Grand Exchange in the skilling category.

In-game examine text: "An empty glass vial."

It has a Grand Exchange buy limit of 13,000 every four hours, a high alchemy value of 1 gp, and item ID 229.

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Vial shows an active flip setup with a margin of +1 gp and 6,242,897 trades over the last 24 hours.

At the buy limit of 13,000 every four hours, max profit per cycle is about 13.0k gp — high margin with healthy liquidity.