Buyer has zero feedback (currently).
They bid on an item during auction with a mid-high ranking bid.
They then 'miss-out' on the winning bid and contact you to say 'I'm new to this and don't understand how bidding works'.
They then offer to buy the item outside of the eBay framework for a higher price.
The scam is to convince you to sand them the goods direct after they pay via PayPal.
The seller no longer has seller protection.
You know what happens next...