Oak plank

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

In-game examine text: "A plank of sturdy oak."

It has a Grand Exchange buy limit of 13,000 every four hours, a high alchemy value of 150 gp, and item ID 8778.

View on OSRS Wiki

Oak Plank shows an active flip setup with a margin of +12 gp and 2,548,242 trades over the last 24 hours.

At the buy limit of 13,000 every four hours, max profit per cycle is about 156.0k gp — high margin with healthy liquidity.