I wish I could help direct you to a place where your friend could purchase a used mill. While I've seen used mixers (Kitchen Aid) on eBay, I don't know that I've ever seen mills. I guess it might be one of those things that if you spend the money to invest in a mill, you use it until it quits. Maybe should could email some of the companys that sell mills -- I'm thinking Marmee Dear or Marilyn Moll at Urban Homemaker for suggestions about where to look. Best of luck finding one.
CheleLew @ homeschoolblogger.com/chelelew