Bought a hammer for 80k because someone 5 minutes earlier had said they wanted to buy one for 100k and I thought I would make a 20k profit. Little did 14 year old me know that the buyer and seller were working together, or were the same person, and I had been tricked into buying a hammer worth 40k for 80k.

That has to be a scam as old as time. Glad I learned that lesson on runescape instead of in real life.