Questionable Buyer

[workday]

I sold an item to a buy on eBay. Once I accepted his offer he requested that I add add a $500 gift card he would pay for.  I immediately suspected a scam and declined the "gift certificate", however, he sent the original money offered for the product to my PayPal account which has now been deposited into my bank account.  I am still suspecting a scam.  Question: Is this a scam? Once the money is deposited into my account and I send off the item to the buyer is there anyway he could retract the money from my account and still keep the product?

Thanks in advance for your help

[kernowlass]

@workday 

That depends on many factors all listed in Paypals seller protection policy for you to read so you can risk assess your transactions.
Legal (bottom right of Paypals pages) > user agreement > seller protection.