<prompt> Human: So I was selling a laptop on a site called LetGo, and about 30 minutes after I posted my ad a woman messaged me asking to buy it.She said she was on a business trip right now I know, this all sounds like a textbook scam and would have her friend pick it up for her.Now this all sounded like a scam to me, but the payment sounded legitimate. She said she would mail the check and only pick up the laptop after it cleared.This is a 600 transaction, so I obviously dont want to be scammed.ThanksOh side note, I dont know if this matters, but she said she would add 20 to the price for me to take the ad down.  <response>: Its a scam.The funds will become available before it clears. Youll think everything is good and release the laptop. The check will come back as invalid and the bank will take the money away and youll be out a laptop. 