I've had similar on the opposite end, had something to sell had someone immediately agreed to asking price but emailed me a "pay £300 to upgrade your paypal account to business first".
Couldn't find anything on the guy here or on Zeroin so didn't want to point fingers without proof, deleted the PM's and decided to avoid him. It was the same bloke both times, insisting on payment as F&F saying the paypal account belongs to his son and he will only accept payment as friend and family. Looked up when he joined the forum though and I believe in November last year.