This isn't going to be a HUGE thread, just a little tutorial/tip thingie I've learned from past experiences.
If you want to make a deal with a new user that isn't trusted, you should probably accept either MoneyPak or Bitcoins. Otherwise, if you are using PayPal, and are SENDING the money, log onto a VPN you've NEVER used on PayPal before. Send the money on the VPN. If it turns out he scammed you, just go back into PayPal, change your password and then open up a dispute saying it was unauthorized. You'll get support within some hours at the longest.
Good luck, hope this helps some of you customers.