As above.
PayPal as goods payment/non-gift may be fairly secure. Especially if you can pay with a Visa/Mastercard you may have the backup of them.
Bank transfer - not sure but I think you'd have to go through small claims court to get your money back. If the bank account details are very different to the persons name then alarm bells should ring.
If not impossible, cash on collection (after viewing) is always best. Or letting someone local to them you know and trust do this on your behalf.