Giant seaweed

Giant Seaweed is a members-only item on the OSRS Grand Exchange in the other category.

In-game examine text: "Seaweed of large size."

It has a Grand Exchange buy limit of 11,000 every four hours, a high alchemy value of 1 gp, and item ID 21504.

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Giant Seaweed shows an active flip setup with a margin of +13 gp and 408,999 trades over the last 24 hours.

At the buy limit of 11,000 every four hours, max profit per cycle is about 143.0k gp — high margin with healthy liquidity.