Well, you can send mail from League or Empire toon to a Priden in Howlem (if the object(s) isn't bound) and re-send that mail to another player of opposite faction as long as the Priden is in Howlem. You just have to know the player names as Pridens in Howlem can't add friends to their list from either faction. (It's convenient to have a toon of your own in both factions).
Another way, I'd imagine, would be incarnation Pridens that haven't left Howlem yet. Incarnations share boutique tab of the bag and if the costume goes there, you can trade it to an imp incarnation Priden (provided the costume isn't bound).
You know, I never thought of this. I have no idea why it never crossed my mind as a possibility.
The costumes had a vendor sell price before, people sold them to faction-neutral vendors hoping it will appear on resale. This method was very risky because chance that the item will appear on resale was not 100%.
people had opposite side faction costumes way before priden race exist so there might be another mean to do that... Maybe with faction change some people bought a lot of costumes of their faction to resell them at a interesting price in the other faction?
nope, there was one very safe npc. It got risky if sb was camping there waiting for free stuff (the guy needed to log off before the item appeard at the resell-optoion)
I do remember something like this awhile back I think in Eljune Bazaar.
Thanks guys for the replies.