Iron bar

Iron Bar is a free-to-play item on the OSRS Grand Exchange in the bars category.

In-game examine text: "It's a bar of iron."

It has a Grand Exchange buy limit of 10,000 every four hours, a high alchemy value of 16 gp, and item ID 2351.

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Iron Bar shows an active flip setup with a margin of +4 gp and 848,125 trades over the last 24 hours.

At the buy limit of 10,000 every four hours, max profit per cycle is about 40.0k gp — high margin with healthy liquidity.