Asking for an email address is really suspicious.
A few years ago I encountered a scam where someone commissioned me to draw a picture and was very generous, offering a high price. When I had already given him the PayPal payment page, he insisted that I give him the email address for my PayPal account.
Shortly after I gave it to him, I received a fake PayPal system email saying there was a problem with the transfer and that I needed to pay some money first to unlock certain features. They also claimed this money would be refunded to me later.
Upon closer inspection, that email was sent from Gmail.A PayPal system email sent from Gmail, lol