If you don't know him well... Cash on the glass. If he is nervous about things (who could blame him), have him bring a deposit instead. Otherwise, thanks for your interest.
I consider this cut and dry. I don't need a third party (PayPal) there to mess up the transaction. Have your security cameras rolling on that spot, and capture him paying, and taking the game. Done, and thanks, nice to meet you. I don't ever understand how it isn't this simple. If he is still nervous, have him bring a friend, but the machine leaves after you lay the cash on the glass.