Watermelon

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

In-game examine text: "A juicy watermelon."

It has a Grand Exchange buy limit of 11,000 every four hours, a high alchemy value of 28 gp, and item ID 5982.

View on OSRS Wiki

Watermelon shows an active flip setup with a margin of +2 gp and 890,518 trades over the last 24 hours.

At the buy limit of 11,000 every four hours, max profit per cycle is about 22.0k gp — high margin with healthy liquidity.