Trim
From AmtWiki
Trim is an easy way to make a plain tunic look fancy.
http://www.cheeptrims.com/ is a online store that has some really nice stuff for pretty cheap. They have minumum length for some trim orders.
http://www.calontirtrim.com/ another online store. Gorgeous trims geared towards SCA and Renn Faries, so of course, perfect for Amtgard.
Check out the Amtgard Resources page for more information.