[quote name='The End']OK, I just bought a 4-pack of Sanctum. I've done a few trades before, so I know how to do the payment thing through Paypal via the Gift option, but this is the first time that I've hosted a group-buy. How do I send a person a copy after they've paid?[/QUOTE]
In steam click on games at the top, and then select manage gifts and guest passes. You enter their steam ID or email and you can gift them the game.