Where can I buy sterile water or 0.9% saline solution for irrigation.?

It is my understanding that sterile water or 0.9% saline solution for irrigation (The Baxter 250 500 1000 ml bottles) need a physician authorization to be pruchased form medical supply. I want to buy a small quantity for my first aid jump bag in the cars. I have some fairly fancy stuff and can handle major traumas with my gear. If I had an AED, oxygen, and a portable suction I would be an ambulance :) Anyway, I just like to go overboard and be prepared for anything. Can anyone point me in a direction or to a supplier that will sell it without a hle - I tried all the big guys such as Moore Medical and they are a no-go.