How to flip Vial of blood in OSRS

Flipping Vial of blood on the Old School RuneScape Grand Exchange currently makes about 91 gp profit per item after the 2% GE tax: buy near 8,137 gp (the instant-sell price) and re-list near 8,395 gp (the instant-buy price).

• Buy at (instant-sell): 8,137 gp
• Sell at (instant-buy): 8,395 gp
• Margin after 2% tax: 91 gp (1.12% ROI)
• Buy limit per 4 hours: 13,000
• 24h volume: 395,564 (extremely liquid)
• Max profit per limit cycle: 1,183,000 gp on 105,781,000 gp of capital

The flip, step by step

1. Place a buy offer at or just above 8,137 gp (the current instant-sell price).
2. Wait for the fill. Vial of blood is extremely liquid right now, so offers at fair prices typically fill within minutes.
3. Re-list at or just below 8,395 gp (the current instant-buy price).
4. The GE takes 167 gp tax (2%) per item when it sells, leaving 91 gp profit each.
5. Repeat up to the buy limit (13,000 per 4 hours), a full cycle is 1,183,000 gp on 105,781,000 gp of capital.

Margins move constantly. Re-check the live Vial of blood numbers and price chart on GrandExchange.com right before committing.