Heavy ballista

The Heavy ballista is a members-only Old School RuneScape item — “A powerful weapon forged from the wreckage of an airship.”. Its Grand Exchange buy limit is 8 per 4 hours. Right now it buys at 971,868 gp and sells at 1,012,225 gp — a net margin of 20,113 gp (2.1% ROI) after the 2% Grand Exchange tax of 20,244 gp. High alchemy yields 570,000 gp.

To flip it, place a buy offer near 971,868 gp and a sell offer near 1,012,225 gp; the spread minus GE tax is your profit. Confidence figures are model estimates from live OSRS Wiki prices, not guarantees — flip responsibly.