It's easy they send me piles of money and I send them stuff....
The best advice anyone has given me (demik actually) if the deal doesn't feel right then walk away.
I once had a 0 poster offer a way higher than expected price for something and the few PM's I got were really weird so what did I do....nothing, never heard from them again.
I've also stalked new posters using their emails etc to see if they were real people. I even emailed one at their work email just for verification.
If people want to trade you can ask for information to verify they are legit and if you ship USPS and print labels online tracking is included.
Just use some common sense. If someone wants what you have bad enough they will jump through hoops, they don't have to like it
But no reason to give paypal needless fees etc either
Heatware?
Ohh forgot about that!
Except no-one has put anything into mine.
let me go fix that right now