Its not against the rules however its much easier if you can do a paypal payment. One its quicker, two very easy for both parties to confirm it being sent and received. It also allows the host an untyped address to ship your cards to from the break (eliminating any transcription errors). last but not least - you as the slot holder have some protection from paypal if anything goes wrong with the break.
Blowouts Resident Wade Boggs Super Collector