Iron ore

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

In-game examine text: "This needs refining."

It has a Grand Exchange buy limit of 13,000 every four hours, a high alchemy value of 10 gp, and item ID 440.

View on OSRS Wiki

Iron Ore shows an active flip setup with a margin of +1 gp and 3,469,164 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.