Posted for bob mackey <n103md@yahoo.com>:

 I have a friend who orders large numbers of oxygen cylinders
  from Luxfer and other companies. He has negotiated
  excellent prices. For example, aluminum D cylinders are under
  $50. The carbon-wrapped equivalent (M22A) is under $200.
  If anyone wants to order an aluminum or composite cylinder,
  let me know and I can add it to one of the upcoming orders.
  
  Follow the links and let me know which model you're interested in:
  http://www.luxfercylinders.com/products/medical/productrange/aluminum.shtml
  http://www.luxfercylinders.com/products/medical/productrange/composite.shtml
  
  Mountain High's medical competition is Chad Therapeutics:
  http://www.chadtherapeutics.com/home.htm
  They make a variety of oxygen conservers, regulators, etc.
  
  For high pressure flexible O2 hoses:
  http://www.spmed.com
  If you've paid $100 for an aircraft hose, you'll be amazed how
  inexpensive custom medical oxygen hoses are. Most high pressure
  hoses are under $20.
  
  For lightweight cylinder valves, Sherwood makes the YVB valve:
  http://www.sherwoodvalve.com/products/medical3.htm
  
    I'll be gone to Hawai'i for a couple of weeks, so don't expect a
    quick reply. Use the email address below to contact me.
  
  -bob mackey
   bob  AT pure-flight DOT com