If you want to aquire the robes from the Bennidictine Order (or any other Order for that matter)....you must join that Order. Those robes/styles of clothing are not warn just because you think that they're cool. With the exception of a few Orders of Nuns....the clothing that religious orders wear haven't changed in over a thousand years. Those orders that do not wear the same style clothing that have been worn for a thousand years are the ones that have been established in the 19th and 20th Centuries. Because the garments that religious Orders wear have specific meaning and idenify you with a particular way of life, religious preference  and Order....I will not tell anyone how to aquire that style of clothing because you (and I'm not accusing you of wanting to do this) could give that religion, Order and way of life a bad reputation if you do something that violates their tennents or do something that would embarrass someone from that Order, religion, way of life while wearing clothing that represents that religion, Order, or way of life. The garments of religious Orders are not to be worn just because it looks neat and distinctive. I agree that the robes that the Monks wear look neat, but, I ain't a Monk and neither are you. So, even though I can get a robe from that Order...I won't because I ain't got the right to wear it and neither do you. Only members of a specific religious Order have the right to wear the clothing associated with that Order.