Trout

Trout is a free-to-play item on the OSRS Grand Exchange in the other category.

In-game examine text: "Some nicely cooked trout."

It has a Grand Exchange buy limit of 6,000 every four hours, a high alchemy value of 6 gp, and item ID 333.

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Trout shows an active flip setup with a margin of +3 gp and 91,592 trades over the last 24 hours.

At the buy limit of 6,000 every four hours, max profit per cycle is about 18.0k gp — high margin with healthy liquidity.