Supercompost

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

In-game examine text: "Super-good for the smallest or largest of plants."

It has a Grand Exchange buy limit of 2,000 every four hours, a high alchemy value of 51 gp, and item ID 6034.

View on OSRS Wiki

Supercompost shows an active flip setup with a margin of +6 gp and 888,846 trades over the last 24 hours.

At the buy limit of 2,000 every four hours, max profit per cycle is about 12.0k gp — high margin with healthy liquidity.