Crests

From Master Sword Wiki

Crests might be considered armor to some, but there really is no benefit in battle (other than making yourself stand out). They provide no armor bonus or Damage Reduction.

Crest of Edana - In my opinion, one of the ugliest things in the game. It is also very overpriced, don't buy it unless you want to burn alot of money on something that you won't want afterwards. [Thothie comments: The "Blue Lobster Bib of Dewm" you are refering to is designed to advertise that you have far too much cash, and are far too l337 to talk to anyone not afluent enough to be wearing the same trés chic clothing ;)]

Guild Crests - The personal Crests of various guilds in the game, worn by the Guild members. Guild exclusive, anyone wearing one who isn't in the guild will usually be dealt with swiftly.

Bonus Crests - There are some bonus crests, hidden throughout the game. These include the infamous Crest of Helena, and Crest of Crow. Others will likely be added in the future. Some of these crests can be sold or exchanged for other items.

Developer Crests - Those who add five or more maps approved for the world recieve their own custom crest to do with as they wilt.

For more details about crests, see the forum article:
http://www.msremake.com/forums/viewtopic.php?t=1968&start=0