How to flip Marrentill seed in OSRS

Flipping Marrentill seed on the Old School RuneScape Grand Exchange currently makes about 4 gp profit per item after the 2% GE tax: buy near 23 gp (the instant-sell price) and re-list near 27 gp (the instant-buy price).

• Buy at (instant-sell): 23 gp
• Sell at (instant-buy): 27 gp
• Margin after 2% tax: 4 gp (17.39% ROI)
• Buy limit per 4 hours: 600
• 24h volume: 20,624 (very liquid)
• Max profit per limit cycle: 2,400 gp on 13,800 gp of capital

The flip, step by step

1. Place a buy offer at or just above 23 gp (the current instant-sell price).
2. Wait for the fill. Marrentill seed is very liquid right now, so offers usually fill within minutes to a quarter hour.
3. Re-list at or just below 27 gp (the current instant-buy price).
4. The GE takes 0 gp tax (2%) per item when it sells, leaving 4 gp profit each.
5. Repeat up to the buy limit (600 per 4 hours), a full cycle is 2,400 gp on 13,800 gp of capital.

Margins move constantly. Re-check the live Marrentill seed numbers and price chart on GrandExchange.com right before committing.