^^Thank you for updating.
The scammer wanted to send you a fake Paypal payment. He has a fake Paypal address from a free email provider. The payment would look real. Its a screen shot of a fake payment. He then will instruct you to pay a mover, shipper/freight or agent. The fake Paypal email from the scammer would say that your Paypal funds will be released when you send the scammer (mover,agent or shipper) money via Western Union or Money Gram. In reality Paypal would never hold your funds.
Log into Paypal directly without any links to check for monies received or call Paypal directly from the number on their site.
If you are selling electronics, Cell phones or computers then the scammer is trying to steal your "item". Your fake funds will be released when you send the scammer a scan copy of a receipt showing you mailed your item.
This same scam works with fake check and money orders. You and your bank will think they are real. After you cash the fake check. Days or weeks later your bank will inform you of the fraud. Your bank will have you repay the monies. Possibly close your account for fraud and report you to Law Enforcement.
The best thing to do is to sell in person face to face in a public place or with someone with you.