Harpoon

The Harpoon is a free-to-play Old School RuneScape item — “Useful for catching really big fish.”. Its Grand Exchange buy limit is 40 per 4 hours. Right now it buys at 377 gp and sells at 377 gp — a net margin of -7 gp (-1.9% ROI) after the 2% Grand Exchange tax of 7 gp. High alchemy yields 3 gp.

To flip it, place a buy offer near 377 gp and a sell offer near 377 gp; the spread minus GE tax is your profit. Confidence figures are model estimates from live OSRS Wiki prices, not guarantees — flip responsibly.