A few things to check quickly if ever you come across on of these scams.
They use Paypal for the payment but want Western Union funds transfer.
Email address and actual domain do not match.
Paypal email address has a different domain.
Any expectation that you as the seller should part with cash before you get your dough is a dead giveaway.
Buyer is happy to buy sight unseen
Be mindful even when using Paypal legitimately, ensure that you transfer the money out and into you bank before you hand over the goods and make sure that you get the buyer to sign for receipt of the goods in good condition.
Paypal protection allows recourse against the seller if the buyer claims goods were not as described, it just not worth the crap you have to go through if you don't have the evidence to hand.
It's a shame, because Paypal is a good mechanism, the clowns just try and leverage the naivety of the general population. Just goes to show that there is still no shortage of scumbags. I've often wondered what a world would be like where there were as many people committed to delivery top quality customer service as there are those who would scam you in the current one.
Cheers
Thy