If they go through checkout they won't see your Paypal details. Unless it's the same as the email address you use for eBay, which they do get, I think.

What is the context? Have you sold? Have you provided your account details in order to sell off-eBay?

Bottom line is Nigeria = scam. Asking the price and availability for a live listing = a scam. Any mention of wire transfers, oceanography/oil rigs, paying the picker upper in cash or Western Union that the 'buyer' has paid into Paypal especially coupled with any mention of payment being in escrow = scam.

The generic answer is change your passwords, run anti-virus and anti-malware scans, don't click on links in emails, always login to the relevant account and see if the alleged transaction has occurred.....