I donated a banner to my chapter as an alumna. It wasn't a flag that could be run up a flag pole to fly in the wind, but it was a display banner with the chapter's letter on it made out of our sorority's colors. It was made out of a canvas-type material and had a metal grommet in each corner so that it could be hung from a wall or ceiling. The banner was really useful to drape from the front of a table for Student Organization fairs, Rush Information nights, formal chapters, a table set up in front of the student union, philanthropy events, etc. I priced several websites before I ordered it and found the best price at
www.joetoga.com I was very pleased with the quality, customer service, etc. I ordered the banner about 4 years ago, but I think Joe Toga is still in business. Now, if you wanted a traditional flag with your organization's crest, in sorority colors, etc, you might check out a local screenprinting or banner business in your college town. I've never ordered anything like that. But I did have a friend make a copy of my sorority crest with an overhead projector. If you were trying to save money and one of your sisters was really artistic, you might try using an overhead projector, fabric markers, etc.