Received an email pertaining to an ad listing I had on gumtree, asked for a quotation if it were to be shipped to Thailand. Sent a paypal invoice, and the person replied saying they had sent the payment, asking me to check my email and spam folder, and that the payment will be released by paypal once the transaction receipt has been verified by paypal. I found this highly suspicious as paypal would not do such a thing, paypal would have alerted me of such activity. I then saw an email in the spam folder posing as a paypal admin notice, but originated from a very dubious address. Called paypal and verified that this was a fake email, and did not proceed any further. No packages were sent out and no lossed were incurred, just a major waste of my time.
Source: Scam Alert Singapore