Single post in Questions About Site Rules 2.0

Hi! I apologize in advance if this question has been answered somewhere else, I tried looking for something related to it, but probably missed it. I just opened a Trade shop on the trades forum, and thought it would be a good idea to put up an Opening raffle. So, for every order of at least 15zc or equivalent I would send the buyer a PM with their raffle ticket, along with keeping track of the ticket list myself. Is this okay? Am I breaking any rules? If it's not allowed, I'll just delete that from the shop thread. Thank you. :)